This work was funded by the Ministry of Education ERC CZ grant LL1205, the Grant Agency of Czech Republic grant 18-17529S, and by ERDF/ESF project Centre for research of pathogenicity and virulence of parasites (No. CZ.02.1.01/0.0/0.0/16_019/0000759).

1. Buffers and Solutions
<ol>
	<li>Prepare the solutions listed below. Degas all buffers for liquid chromatography. Add ADP, benzamidine, and protease inhibitors just before use.
	<ol>
		<li>Prepare buffer A: 50 mM Tris buffer with hydrochloric acid (Tris-HCl) pH 8.0, 0.25 M sucrose, 5 mM benzamidine, 5 mM aminocaproic acid (ACA), and protease inhibitors (10 &#181;M amastatin, 50 &#181;M bestatin, 50 &#181;M pepstatin, 50 &#181;M leupeptin, and 50 &#181;M diprotin A).</li>
		<li>Prepare buffer B: 50 mM Tris-HCl pH 8.0, 0.25 M sucrose, 4 mM ethylenediaminetetraacetic acid (EDTA), 5 mM benzamidine, 5 mM ACA, 1 mM ADP, and protease inhibitors (10 &#181;M amastatin, 50 &#181;M bestatin, 50 &#181;M pepstatin, 50 &#181;M leupeptin, and 50 &#181;M diprotin A).</li>
		<li>Prepare Q-column buffer: 20 mM Tris-HCl pH 8.0, 4 mM EDTA, 10 mM MgSO4, 5 mM benzamidine, 5 mM ACA, and 1 mM ADP.</li>
		<li>Prepare Q-column elution buffer: Q-column buffer with 1 M NaCl.</li>
		<li>Prepare&#160;SEC&#160;buffer: 20 mM Tris-HCl pH 8.0, 10 mM MgSO4, 100 mM NaCl, 1 mM ADP.</li>
		<li>Prepare chloroform saturated with 2 M Tris-HCl pH 8.5. Mix chloroform with 2 M Tris-HCl pH 8.5 in approximately 1:1 ratio in a screw-cap bottle, shake, let the organic and aqueous phases separate, and measure pH in the upper aqueous layer with a strip of pH-indicator paper. Store at room temperature. Just before use, shake again and let the phases separate. Use the lower chloroform layer. 
		CAUTION: Chloroform is volatile and irritating to eyes and skin. Work in a fume hood. Use safety spectacles when shaking.</li>
	</ol>
	</li>
</ol>
2. Preparation of sub-mitochondrial Particles
<ol>
	<li>Resuspend mitochondrial vesicles (mitoplasts) isolated by hypotonic lysis25 from 1 x 1011 to 2 x 1011 cells of procyclic T. brucei in 5 mL of ice-cold buffer A. Keep the sample chilled until step 3.2.</li>
	<li>Determine the protein concentration in the suspension by the bicinchoninic acid (BCA) protein assay26 according to the manufacturer&#39;s instructions.
	<ol>
		<li>Use a bovine serum albumin (BSA) dilution series in ultrapure water to construct the standard curve. Dilute a small amount of sample 20 - 100 times with ultrapure water to fit into the range of BSA standards.</li>
		<li>Calculate the total protein amount in the sample and bring the protein concentration to 16 mg/mL by diluting it with additional buffer A.</li>
	</ol>
	</li>
	<li>Fragment mitoplasts into inverted vesicles and membrane pieces by sonication of the suspension 7x for 15 s with a total energy of 70 to 100 J per impulse with a microtip with a diameter of 3.9 mm. If the ultrasonic homogenizer does not display the energy output, start the optimization at 50% of the maximal power. Incubate the sample on ice for 30 s between impulses. After the sonication, the suspension becomes slightly darker.</li>
	<li>Sediment the membrane fragments by ultracentrifugation at 54,000 x g for 16 h or at 98,000 x g for 5 h at 4 &#176;C. Decant the supernatant and proceed with the chloroform extraction, or flash-freeze the sediment in liquid nitrogen and store it at -80 &#176;C.</li>
</ol>
3. Release of F1-ATPase from Membrane by Chloroform
<ol>
	<li>Resuspend the pellet of mitochondrial membranes in buffer B with the aid of a small Dounce homogenizer. Calculate the volume of buffer B based on the total amount of buffer A used in steps 2.1 and 2.2 using the following formula: volume (buffer B) = volume (buffer A) x 12/21. Transfer the suspension to a 15- or 50-mL conical tube.</li>
	<li>Remove the sample from ice and, from now on, keep the sample and all solutions to be used at room temperature.</li>
	<li>Add chloroform saturated with 2 M Tris-HCl pH 8.5; the volume of chloroform to be added equals half the volume of the suspension. Close the cap tightly. Shake it vigorously for exactly 20 s. Centrifuge it immediately at 8,400 x g for 5 min at room temperature.</li>
	<li>Transfer the upper cloudy aqueous phase to 1.6-mL microtubes. Add protease inhibitors (10 &#181;M amastatin, 50 &#181;M bestatin, 50 &#181;M pepstatin, 50 &#181;M leupeptin, and 50 &#181;M diprotin A) to replace the inhibitors removed by the chloroform treatment. Centrifuge the samples at 13,000 x g for 30 min at room temperature. Transfer the supernatant to fresh microtubes and repeat the centrifugation to remove any insoluble material.</li>
</ol>
4. Anion-exchange Chromatography
<ol>
	<li>Equilibrate the 5-mL anion exchange (Q) column attached to a fast-protein liquid chromatography system with the Q-column buffer at a flow rate of 5 mL/min until the absorbance at 280 nm and the conductivity stabilize (approximately 50 mL of buffer).</li>
	<li>Load the supernatant from step 3.3 on the equilibrated column at a flow rate of 1 mL/min. Wait until the absorbance at 280 nm stabilizes at the background. Apply a 25-mL linear gradient of the Q-column elution buffer from 0% to 100% at a flow rate of 0.5 mL/min. Collect 1-mL fractions.</li>
	<li>Assay the individual fractions corresponding to the major elution peak for ATP hydrolytic activity by the Pullman ATPase assay2 at pH 8.0. Use 10 &#181;L of each fraction per 1 mL of reaction mixture.Pool the fractions that exhibit ATPase activity. Optionally, separate 10 &#181;L of each fraction on sodium dodecyl phosphate polyacrylamide gel electrophoresis (SDS-PAGE) and stain the gel by Coomassie Blue to visualize individual F1-ATPase subunits and contaminating proteins.</li>
	<li>Concentrate the pooled sample by membrane ultrafiltration using a spin column with a 100,000 MWCO PES filter to 200 - 500 &#181;L. Proceed to SEC or store the sample overnight at room temperature.</li>
</ol>
5. Size-exclusion Chromatography
<ol>
	<li>Equilibrate the SEC column attached to a liquid chromatography system with at least 48 mL (two column volumes) of the SEC buffer at a flow rate of 0.5 mL/min.</li>
	<li>Apply the sample on the column and run chromatography at a flow rate of 0.25 mL/min. Collect 0.25-mL fractions.</li>
	<li>Run 10 &#181;L of the fractions that correspond to the peaks of the UV280nm absorbance trace on SDS-PAGE and stain them by Coomassie Blue. The first major peak contains the F1-ATPase. Assay the fractions corresponding to this peak for the ATP hydrolytic activity and azide sensitivity by the Pullman ATPase assay. Determine the protein concentration by the BCA assay.</li>
	<li>Keep the purified F1-ATPase at room temperature and use it within 3 d after purification for downstream applications. Alternatively, concentrate the sample using a spin column with a 100,000 MWCO PES filter to &#62; 1.5 mg/mL, precipitate it by mixing it with saturated ammonium sulfate adjusted to pH 8.0 (1.2x the volume), and store it at 4 &#176;C.</li>
</ol>

<ol>
	<li>Walker, J. E., Wikstr&#246;m, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure,+mechanism+and+regulation+of+ATP+synthases.">Structure, mechanism and regulation of ATP synthases.</a> Mechanisms of Primary Energy Transduction in Biology. , 338-373 (2017).</li><li>Pullman, M. E., Penefsky, H. S., Datta, A., Racker, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+resolution+of+the+enzymes+catalyzing+oxidative+phosphorylation.+I.+Purification+and+properties+of+soluble+dinitrophenol-stimulated+adenosine+triphosphatase.">Partial resolution of the enzymes catalyzing oxidative phosphorylation. I. Purification and properties of soluble dinitrophenol-stimulated adenosine triphosphatase.</a> The Journal of Biological Chemistry. 235, 3322-3329 (1960).</li><li>Schatz, G., Penefsky, H. S., Racker, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+resolution+of+the+enzymes+catalyzing+oxidative+phosphorylation.">Partial resolution of the enzymes catalyzing oxidative phosphorylation.</a> XIV. The Journal of Biological Chemistry. 242 (10), 2552-2560 (1967).</li><li>Racker, E., Horstman, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+resolution+of+the+enzymes+catalyzing+oxidative+phosphorylation.+13.+Structure+and+function+of+submitochondrial+particles+completely+resolved+with+respect+to+coupling+factor.">Partial resolution of the enzymes catalyzing oxidative phosphorylation. 13. Structure and function of submitochondrial particles completely resolved with respect to coupling factor.</a> The Journal of Biological Chemistry. 242 (10), 2547-2551 (1967).</li><li>Senior, A. E., Brooks, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Studies+on+the+mitochondrial+oligomycin-insensitive+ATPase.+I.+An+improved+method+of+purification+and+the+behavior+of+the+enzyme+in+solutions+of+various+depolymerizing+agents.">Studies on the mitochondrial oligomycin-insensitive ATPase. I. An improved method of purification and the behavior of the enzyme in solutions of various depolymerizing agents.</a> Archives of Biochemistry and Biophysics. 140 (1), 257-266 (1970).</li><li>Tzagoloff, A., Meagher, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assembly+of+the+mitochondrial+membrane+system.+V.+Properties+of+a+dispersed+preparation+of+the+rutamycin-sensitive+adenosine+triphosphatase+of+yeast+mitochondria.">Assembly of the mitochondrial membrane system. V. Properties of a dispersed preparation of the rutamycin-sensitive adenosine triphosphatase of yeast mitochondria.</a> The Journal of Biological Chemistry. 246 (23), 7328-7336 (1971).</li><li>Beechey, R. B., Hubbard, S. A., Linnett, P. E., Mitchell, A. D., Munn, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+and+rapid+method+for+the+preparation+of+adenosine+triphosphatase+from+submitochondrial+particles.">A simple and rapid method for the preparation of adenosine triphosphatase from submitochondrial particles.</a> Biochemical Journal. 148 (3), 533-537 (1975).</li><li>Tyler, D. D., Webb, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+properties+of+the+adenosine+triphosphatase+released+from+the+liver+mitochondrial+membrane+by+chloroform.">Purification and properties of the adenosine triphosphatase released from the liver mitochondrial membrane by chloroform.</a> Biochemical Journal. 178 (2), 289-297 (1979).</li><li>Hack, E., Leaver, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+alpha-subunit+of+the+maize+F1-ATPase+is+synthesised+in+the+mitochondrion.">The alpha-subunit of the maize F1-ATPase is synthesised in the mitochondrion.</a> The EMBO Journal. 2 (10), 1783-1789 (1983).</li><li>Dunn, P. P., Slabas, A. R., Moore, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+F1-ATPase+from+cuckoo-pint+(Arum+maculatum)+mitochondria.+A+comparison+of+subunit+composition+with+that+of+rat+liver+F1-ATPase.">Purification of F1-ATPase from cuckoo-pint (Arum maculatum) mitochondria. A comparison of subunit composition with that of rat liver F1-ATPase.</a> Biochemical Journal. 225 (3), 821-824 (1985).</li><li>Satre, M., Bof, M., Vignais, P. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interaction+of+Escherichia+coli+adenosine+triphosphatase+with+aurovertin+and+citreoviridin:+inhibition+and+fluorescence+studies.">Interaction of Escherichia coli adenosine triphosphatase with aurovertin and citreoviridin: inhibition and fluorescence studies.</a> Journal of Bacteriology. 142 (3), 768-776 (1980).</li><li>Abrahams, J. P., Leslie, A. G., Lutter, R., Walker, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+at+2.8+&#197;+resolution+of+F1ATPase+from+bovine+heart+mitochondria.">Structure at 2.8 &#197; resolution of F1ATPase from bovine heart mitochondria.</a> Nature. 370 (6491), 621-628 (1994).</li><li>Lutter, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystallization+of+F1-ATPase+from+bovine+heart+mitochondria.">Crystallization of F1-ATPase from bovine heart mitochondria.</a> Journal of Molecular Biology. 229 (3), 787-790 (1993).</li><li>Kabaleeswaran, V., Puri, N., Walker, J. E., Leslie, A. G., Mueller, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+features+of+the+rotary+catalytic+mechanism+revealed+in+the+structure+of+yeast+F1-ATPase.">Novel features of the rotary catalytic mechanism revealed in the structure of yeast F1-ATPase.</a> The EMBO Journal. 25 (22), 5433-5442 (2006).</li><li>Shirakihara, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+a+thermophilic+F1-ATPase+inhibited+by+an+epsilon-subunit:+deeper+insight+into+the+epsilon-inhibition+mechanism.">Structure of a thermophilic F1-ATPase inhibited by an epsilon-subunit: deeper insight into the epsilon-inhibition mechanism.</a> The FEBS Journal. 282 (15), 2895-2913 (2015).</li><li>Stocker, A., Keis, S., Cook, G. M., Dimroth, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification,+crystallization,+and+properties+of+F1-ATPase+complexes+from+the+thermoalkaliphilic+Bacillus+sp.+strain+TA2.A1.">Purification, crystallization, and properties of F1-ATPase complexes from the thermoalkaliphilic Bacillus sp. strain TA2.A1.</a> Journal of Structural Biology. 152 (2), 140-145 (2005).</li><li>Ferguson, S. A., Cook, G. M., Montgomery, M. G., Leslie, A. G., Walker, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+the+thermoalkaliphilic+F1-ATPase+from+Caldalkalibacillus+thermarum.">Regulation of the thermoalkaliphilic F1-ATPase from Caldalkalibacillus thermarum.</a> Proceedings of the National Academy of Sciences of the United States of America. 113 (39), 10860-10865 (2016).</li><li>Cataldi de Flombaum, M. A., Frasch, A. C. C., Stoppani, A. O. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenosine+triphosphatase+from+Trypanosoma+cruzi:+purification+and+properties.">Adenosine triphosphatase from Trypanosoma cruzi: purification and properties.</a> Comparative Biochemistry and Physiology Part B: Comparative Biochemistry. 65 (1), 103-109 (1980).</li><li>Williams, N., Frank, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mitochondrial+ATP+synthase+of+Trypanosoma+brucei:+isolation+and+characterization+of+the+intact+F1+moiety.">The mitochondrial ATP synthase of Trypanosoma brucei: isolation and characterization of the intact F1 moiety.</a> Molecular and Biochemical Parasitology. 43 (1), 125-132 (1990).</li><li>Higa, A. I., Cazzulo, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mg2+-activated+adenosine+triphosphatase+from+Crithidia+fasciculata:+purification+and+inhibition+by+suramin+and+efrapeptin.">Mg2+-activated adenosine triphosphatase from Crithidia fasciculata: purification and inhibition by suramin and efrapeptin.</a> Molecular and Biochemical Parasitology. 3 (6), 357-367 (1981).</li><li>Walker, J. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+structure+and+subunit+stoichiometry+of+F1-ATPase+from+bovine+mitochondria.">Primary structure and subunit stoichiometry of F1-ATPase from bovine mitochondria.</a> Journal of Molecular Biology. 184 (4), 677-701 (1985).</li><li>Mueller, D. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ni-chelate-affinity+purification+and+crystallization+of+the+yeast+mitochondrial+F1-ATPase.">Ni-chelate-affinity purification and crystallization of the yeast mitochondrial F1-ATPase.</a> Protein Expression and Purification. 37 (2), 479-485 (2004).</li><li>Gahura, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+F1-ATPase+from+Trypanosoma+brucei+is+elaborated+by+three+copies+of+an+additional+p18-subunit.">The F1-ATPase from Trypanosoma brucei is elaborated by three copies of an additional p18-subunit.</a> The FEBS Journal. 285 (3), 614-628 (2018).</li><li>Montgomery, M. G., Gahura, O., Leslie, A. G. W., Zikova, A., Walker, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ATP+synthase+from+Trypanosoma+brucei+has+an+elaborated+canonical+F1-domain+and+conventional+catalytic+sites.">ATP synthase from Trypanosoma brucei has an elaborated canonical F1-domain and conventional catalytic sites.</a> Proceedings of the National Academy of Sciences of the United States of America. 115 (9), 2102-2107 (2018).</li><li>Schneider, A., Charriere, F., Pusnik, M., Horn, E. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+mitochondria+from+procyclic+Trypanosoma+brucei.">Isolation of mitochondria from procyclic Trypanosoma brucei.</a> Methods in Molecular Biology. 372, 67-80 (2007).</li><li>Smith, P. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+protein+using+bicinchoninic+acid.">Measurement of protein using bicinchoninic acid.</a> Analytical Biochemistry. 150 (1), 76-85 (1985).</li><li>Wirtz, E., Leal, S., Ochatt, C., Cross, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+tightly+regulated+inducible+expression+system+for+conditional+gene+knock-outs+and+dominant-negative+genetics+in+Trypanosoma+brucei.">A tightly regulated inducible expression system for conditional gene knock-outs and dominant-negative genetics in Trypanosoma brucei.</a> Molecular and Biochemical Parasitology. 99 (1), 89-101 (1999).</li><li>Speijer, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+the+respiratory+chain+from+cultured+Crithidia+fasciculata.">Characterization of the respiratory chain from cultured Crithidia fasciculata.</a> Molecular and Biochemical Parasitology. 85 (2), 171-186 (1997).</li><li>Nelson, R. E., Aphasizheva, I., Falick, A. M., Nebohacova, M., Simpson, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+I-complex+in+Leishmania+tarentolae+is+an+uniquely-structured+F1-ATPase.">The I-complex in Leishmania tarentolae is an uniquely-structured F1-ATPase.</a> Molecular and Biochemical Parasitology. 135 (2), 221-224 (2004).</li><li>Carbajo, R. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+the+N-terminal+domain+of+the+OSCP+subunit+of+bovine+F1Fo-ATP+synthase+interacts+with+the+N-terminal+region+of+an+alpha+subunit.">How the N-terminal domain of the OSCP subunit of bovine F1Fo-ATP synthase interacts with the N-terminal region of an alpha subunit.</a> Journal of Molecular Biology. 368 (2), 310-318 (2007).</li><li>Bowler, M. W., Montgomery, M. G., Leslie, A. G., Walker, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ground+state+structure+of+F1-ATPase+from+bovine+heart+mitochondria+at+1.9+&#197;+resolution.">Ground state structure of F1-ATPase from bovine heart mitochondria at 1.9 &#197; resolution.</a> The Journal of Biological Chemistry. 282 (19), 14238-14242 (2007).</li></ol>

The authors have nothing to disclose.

The protocol for F1-ATPase purification from T. brucei was developed based on previously published methods for the isolation of F1-ATPase complexes from other species13,14. The method does not require any genetic modification (e.g., tagging) and yields a fully active complex with all subunits present. The crucial step is the chloroform-facilitated release of the F1-ATPase from the membrane-attached part of the en...

The F-type ATP synthases are membrane-bound rotating multiprotein complexes that couple proton translocation across energy-transducing membranes of bacteria, mitochondria, and chloroplasts with the formation of ATP. Molecular details of the rotational mechanism of ATP synthesis are known mainly because of structural studies of purified bacterial and mitochondrial ATP synthases and their subcomplexes1. F-type ATP synthase is organized into membrane-intrinsic and membrane-extrinsic moieties. The membrane-extrinsic part, known as F1-ATPase, contains three catalytic sites, where the phosphorylation of adenosine diphosphate (ADP) to ATP or the reverse reaction occurs. F1-ATPase can be released experimentally from the membrane-intrinsic moiety while retaining its ability to hydrolyze, but not synthesize, ATP. The membrane-bound sector, called Fo, mediates protein translocation, which drives the rotation of the central part of the enzyme. The F1 and Fo sectors are connected by the&#160;central and peripheral stalks.
The first attempts to purify the F1-ATPase from budding yeast and bovine heart mitochondria date back to the 1960s. These protocols used extracted mitochondria, which were disrupted by sonication, fractionated by ammonium or protamine sulfate precipitation, followed by optional chromatography step(s) and heat treatment2,3,4,5,6. The purification was greatly improved and simplified by the use of chloroform, which readily releases the F1-ATPase from the mitochondrial membrane fragments7. The chloroform extraction was then used to extract F1-ATPases from various animal, plant, and bacterial sources (e.g., rat liver8, corn9, Arum maculatum10, and Escherichia coli11). Further purification of the chloroform-released F1-ATPase by affinity or size-exclusion chromatography (SEC) yielded a highly pure protein complex, which was suitable for high-resolution structure determination by X-ray crystallography, as documented by the structures of F1-ATPase from bovine heart12,13 and Saccharomyces cerevisiae14. F1-ATPase structures were also determined from organisms that are difficult to cultivate and, thus, the amount of the initial biological material was limited. In this case, the F1-ATPase subunits were artificially expressed and assembled into the complex in E. coli, and the whole heterologous enzyme was purified by affinity chromatography via a tagged subunit. Such approach led to the determination of F1-ATPase structures from two thermophilic bacterial species, Geobacillus stearothermophilus15 and Caldalkalibacillus thermarum16,17. However, this methodology is rather unsuitable for eukaryotic F1-ATPases since it relies on the prokaryotic protheosynthetic apparatus, posttranslational processing, and complex assembly.
The chloroform-based extraction was previously used to isolate F1-ATPases from unicellular digenetic parasites Trypanosoma cruzi18 and T. brucei19, important mammalian pathogens causing American and African trypanosomiases, respectively, and from monogenic insect parasite Crithidia fasciculata20. These purifications led only to a simple description of the F1-ATPases, since no downstream applications were used to fully characterize the composition, structure, and enzymatic properties of the complex. This article describes an optimized method for F1-ATPase purification from the cultured insect life cycle stage of T. brucei. The method is developed based on the established protocols for isolation of bovine and yeast F1-ATPases21,22. The procedure yields highly pure and homogeneous enzyme suitable for in vitro enzymatic and inhibitory assays, detailed proteomic characterization by mass spectrometry23, and structure determination24. The purification protocol and the knowledge of the F1-ATPase structure at the atomic level opens a possibility to design screens to identify small-molecule inhibitors, and aid in the development of new drugs against African trypanosomiases. Moreover, the protocol can be adapted to purify F1-ATPase from other organisms.

<table>
	<tbody>
		<tr>
			<td>Chemicals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adenosin Diphosphate Disodium Salt (ADP)</td>
			<td>Applichem</td>
			<td>A0948</td>
			<td></td>
		</tr>
		<tr>
			<td>Amastatin Hydrochloride</td>
			<td>Glantham Life Sciences</td>
			<td>GA1330</td>
			<td></td>
		</tr>
		<tr>
			<td>Aminocaproic Acid</td>
			<td>Applichem</td>
			<td>A2266</td>
			<td></td>
		</tr>
		<tr>
			<td>BCA Protein Assay Kit</td>
			<td>ThermoFischer Scientific/Pierce</td>
			<td>23225</td>
			<td></td>
		</tr>
		<tr>
			<td>Benzamidine Hydrochloride</td>
			<td>Calbiochem</td>
			<td>199001</td>
			<td></td>
		</tr>
		<tr>
			<td>Bestatin Hydrochloride</td>
			<td>Sigma Aldrich/Merck</td>
			<td>B8385</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>cOmplete Tablets, Mini EDTA-free</td>
			<td>Roche</td>
			<td>4693159001</td>
			<td>Protease inhibitor cocktail tablets</td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic Acid (EDTA)</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric Acid</td>
			<td>Any supplier</td>
			<td></td>
			<td>For pH adjustment</td>
		</tr>
		<tr>
			<td>Ile-Pro-Ile</td>
			<td>Sigma Aldrich/Merck</td>
			<td>I9759</td>
			<td>Alias Diprotin A</td>
		</tr>
		<tr>
			<td>Leupeptin</td>
			<td>Sigma Aldrich/Merck</td>
			<td>L2884</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Sulfate Heptahydrate</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pepstatin A</td>
			<td>Sigma Aldrich/Merck</td>
			<td>P5318</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein Electrophoresis System</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tris</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Consumables</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge Tubes for SW60Ti, Polyallomer</td>
			<td>Beckman Coulture</td>
			<td>328874</td>
			<td></td>
		</tr>
		<tr>
			<td>DounceTissues Homogenizer 2 mL</td>
			<td>Any supplier</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Vacuum Filtration Device</td>
			<td>Sartorius</td>
			<td>516-7017</td>
			<td>Degasing solutions for liquid chromatography</td>
		</tr>
		<tr>
			<td>HiTrap Q HP, 5 mL</td>
			<td>GE Healthcare Life Sciences</td>
			<td>17115401</td>
			<td>Anion exchange chromatography column</td>
		</tr>
		<tr>
			<td>Regenaretad Cellulose Membrane Filters, pore size 0.45 &#956;m, diameter 47 mm</td>
			<td>Sartorius</td>
			<td>18406--47------N</td>
			<td>Degasing solutions for liquid chromatography</td>
		</tr>
		<tr>
			<td>Superdex 200 Increase 10/300 GL</td>
			<td>GE Healthcare Life Sciences</td>
			<td>29091596</td>
			<td>Size-exclusion chromatography column</td>
		</tr>
		<tr>
			<td>Vivaspin 6 MWCO 100 kDa PES</td>
			<td>Sartorius</td>
			<td>VS0641</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>AKTA Pure 25</td>
			<td>GE Healthcare Life Sciences</td>
			<td>29018224</td>
			<td>Or similar FPLC system</td>
		</tr>
		<tr>
			<td>Spectrophotometer Shimadzu UV-1601</td>
			<td>Shimadzu</td>
			<td></td>
			<td>Or similar spectrophotometer with kinetic assay mode</td>
		</tr>
		<tr>
			<td>Ultracentrifuge Beckman Optima with SW60Ti Rotor</td>
			<td>Beckman Coulture</td>
			<td></td>
			<td>Or similar ultracentrifuge and rotor</td>
		</tr>
		<tr>
			<td>Ultrasonic Homogenizer with Thin Probe, Model 3000</td>
			<td>BioLogics</td>
			<td>0-127-0001</td>
			<td>Or similar ultrasonic homogenizer</td>
		</tr>
	</tbody>
</table>

isolation of f1-atpase from the parasitic protist trypanosoma brucei

F1-ATPase is a membrane-extrinsic catalytic subcomplex of F-type ATP synthase, an enzyme that uses the proton motive force across biological membranes to produce adenosine triphosphate (ATP). The isolation of the intact F1-ATPase from its native source is an essential prerequisite to characterize the enzyme&#39;s protein composition, kinetic parameters, and sensitivity to inhibitors. A highly pure and homogeneous F1-ATPase can be used for structural studies, which provide insight into molecular mechanisms of ATP synthesis and hydrolysis. This article describes a procedure for the purification of the F1-ATPase from Trypanosoma brucei, the causative agent of African trypanosomiases. The F1-ATPase is isolated from mitochondrial vesicles, which are obtained by hypotonic lysis from in vitro cultured trypanosomes. The vesicles are mechanically fragmented by sonication and the F1-ATPase is released from the inner mitochondrial membrane by the chloroform extraction. The enzymatic complex is further purified by consecutive anion exchange and size-exclusion chromatography. Sensitive mass spectrometry techniques showed that the purified complex is devoid of virtually any protein contaminants and, therefore, represents suitable material for structure determination by X-ray crystallography or cryo-electron microscopy. The isolated F1-ATPase exhibits ATP hydrolytic activity, which can be inhibited fully by sodium azide, a potent inhibitor of F-type ATP synthases. The purified complex remains stable and active for at least three days at room temperature. Precipitation by ammonium sulfate is used for long-term storage. Similar procedures have been used for the purification of F1-ATPases from mammalian and plant tissues, yeasts, or bacteria. Thus, the presented protocol can serve as a guideline for the F1-ATPase isolation from other organisms.

A typical purification (Figure 1) starts with mitochondrial vesicles (mitoplasts) isolated on the Percoll gradient from hypotonically lysed 1 x 1011 to 2 x 1011 procyclic T. brucei cells25 cultured in standard glucose-rich SDM-79 medium27. The mitoplasts are fragmented by sonication, spun, and the matrix-containing supernatant is discarded. Mitochondrial membranes are treated with ...

Watch this Scientific Journal Video about Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei at JoVE.com

Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei

This protocol describes the purification of F1-ATPase from the cultured insect stage of Trypanosoma brucei. The procedure yields a highly pure, homogeneous, and active complex suitable for structural and enzymatic studies.

Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei

F1-ATPase is a membrane-extrinsic catalytic subcomplex of F-type ATP synthase, an enzyme that uses the proton motive force across biological membranes to ...

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7.2K Views.  Czech Academy of Science, Institute of Parasitology. This protocol describes the purification of F1-ATPase from the cultured insect stage of Trypanosoma brucei. The procedure yields a highly pure, homogeneous, and active complex suitable for structural and enzymatic studies.

Video: Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei

Isolation of Cognate RNA-protein Complexes from Cells Using Oligonucleotide-directed Elution

Ribonucleoprotein particles direct the biogenesis and post-transcriptional regulation of all mRNAs through distinct combinations of RNA binding proteins. They are composed of position-dependent, cis-acting RNA elements and unique combinations of RNA binding proteins. Defining the composition of a specific RNP is essential to achieving a fundamental understanding of gene regulation. The isolation of a select RNP is akin to finding a needle in a haystack. Here, we demonstrate an approach to isolate RNPs associated at the 5' untranslated region of a select mRNA in asynchronous, transfected cells. This cognate RNP has been demonstrated to be necessary for the translation of select viruses and cellular stress-response genes.
The demonstrated RNA-protein co-precipitation protocol is suitable for the downstream analysis of protein components through proteomic analyses, immunoblots, or suitable biochemical identification assays. This experimental protocol demonstrates that DHX9/RNA helicase A is enriched at the 5' terminus of cognate retroviral RNA and provides preliminary information for the identification of its association with cell stress-associated huR and junD cognate mRNAs.

This manuscript describes an approach to isolate select cognate RNPs formed in eukaryotic cells via a specific oligonucleotide-directed enrichment. We demonstrate the applicability of this approach by isolating a cognate RNP bound to the retroviral 5' untranslated region that is composed of DHX9/RNA helicase A.

Ribonucleoprotein particles direct the biogenesis and post-transcriptional regulation of all mRNAs through distinct combinations of RNA binding proteins. ...

An Efficient Method for the Isolation of Highly Purified RNA from Seeds for Use in Quantitative Transcriptome Analysis

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as industrial materials. Gene expression profiles are powerful tools for investigating metabolic regulation in plant cells. Therefore, detailed, accurate gene expression profiles during seed development are required for crop breeding. Acquiring highly purified RNA is essential for producing these profiles. Efficient methods are needed to isolate highly purified RNA from seeds. Here, we describe a method for isolating RNA from seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method enables highly purified RNA to be obtained from seeds without the use of phenol, chloroform, or additional processes for RNA purification. This method is applicable to Arabidopsis, rapeseed, and soybean seeds. Our method will be useful for monitoring the expression patterns of low level transcripts in developing and mature seeds.

We have succeeded in establishing a method for RNA isolation from plant seeds containing large amounts of oils, proteins, and polyphenols, which have inhibitory effects on high-purity RNA isolation. Our method is suitable for monitoring the expression of genes with low level transcripts in seeds.

Plant seeds accumulate large amounts of storage reserves comprising biodegradable organic matter. Humans rely on seed storage reserves for food and as ...

Tandem Affinity Purification of Protein Complexes from Eukaryotic Cells

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo identification of novel subunits and post-translational modifications. Bacterial systems allow for the expression and purification of a wide variety of single polypeptides and protein complexes. However, this system does not enable the purification of protein subunits that contain post-translational modifications (e.g., phosphorylation and acetylation), and the identification of novel regulatory subunits that are only present/expressed in the eukaryotic system. Here, we provide a detailed description of a novel, robust, and efficient tandem affinity purification (TAP) method using STREP- and FLAG-tagged proteins that facilitates the purification of protein complexes with transiently or stably expressed epitope-tagged proteins from eukaryotic cells. This protocol can be applied to characterize protein complex functionality, to discover post-translational modifications on complex subunits, and to identify novel regulatory complex components by mass spectrometry. Notably, this TAP method can be applied to study protein complexes formed by eukaryotic or pathogenic (viral and bacterial) components, thus yielding a wide array of downstream experimental opportunities. We propose that researchers working with protein complexes could utilize this approach in many different ways.

We describe here a novel, robust, and efficient tandem affinity purification (TAP) method for the expression, isolation, and characterization of protein complexes from eukaryotic cells. This protocol could be utilized for the biochemical characterization of discrete complexes as well as the identification of novel interactors and post-translational modifications that regulate their function.

The purification of active protein-protein and protein-nucleic acid complexes is crucial for the characterization of enzymatic activities and de novo ...

Isolation and Respiratory Measurements of Mitochondria from Arabidopsis thaliana

Mitochondria are essential organelles involved in numerous metabolic pathways in plants, most notably the production of adenosine triphosphate (ATP) from the oxidation of reduced compounds such as nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2). The complete annotation of the Arabidopsis thaliana genome has established it as the most widely used plant model system, and thus the need to purify mitochondria from a variety of organs (leaf, root, or flower) is necessary to fully utilize the tools that are now available for Arabidopsis to study mitochondrial biology. Mitochondria are isolated by homogenization of the tissue using a variety of approaches, followed by a series of differential centrifugation steps producing a crude mitochondrial pellet that is further purified using continuous colloidal density gradient centrifugation. The colloidal density material is subsequently removed by multiple centrifugation steps. Starting from 100 g of fresh leaf tissue, 2 - 3 mg of mitochondria can be routinely obtained. Respiratory experiments on these mitochondria display typical rates of 100 - 250 nmol O2 min-1 mg total mitochondrial protein-1 (NADH-dependent rate) with the ability to use various substrates and inhibitors to determine which substrates are being oxidized and the capacity of the alternative and cytochrome terminal oxidases. This protocol describes an isolation method of mitochondria from Arabidopsis thaliana leaves using continuous colloidal density gradients and an efficient respiratory measurements of purified plant mitochondria.

Isolation and Respiratory Measurements of Mitochondria from Arabidopsis thaliana

As mitochondria are only a small percentage of the plant cell, they need to be purified for a range of studies. Mitochondria can be isolated from a variety of plant organs by homogenization, followed by differential and density gradient centrifugation to obtain a highly purified mitochondrial fraction.

Mitochondria are essential organelles involved in numerous metabolic pathways in plants, most notably the production of adenosine triphosphate (ATP) from ...

Protein Digestion, Ultrafiltration, and Size Exclusion Chromatography to Optimize the Isolation of Exosomes from Human Blood Plasma and Serum

Exosomes, a type of nanovesicle released from all cell types, can be isolated from any bodily fluid. The contents of exosomes, including proteins and RNAs, are unique to the cells from which they are derived and can be used as indicators of disease. Several common enrichment protocols, including ultracentrifugation, yield exosomes laden with soluble protein contaminants. Specifically, we have found that the most abundant proteins within blood often co-purify with exosomes and can confound downstream proteomic studies, thwarting the identification of low abundance biomarker candidates. Of additional concern is irreproducibility of exosome protein quantification due to inconsistent representation of non-exosomal protein levels. The protocol detailed here was developed to remove non-exosomal proteins that co-purify along with exosomes, adding rigor to the exosome purification process. Five methods were compared using paired blood plasma and serum from five donors. Analysis using nanoparticle tracking analysis and micro bicinchoninic acid protein assay revealed that a combined protocol utilizing ultrafiltration and size exclusion chromatography yielded the optimal vesicle enrichment and soluble protein removal. Western blotting was used to verify that the expected abundant blood proteins, including albumin and apolipoproteins, were depleted.

Here, we present a protocol to purify exosomes from both plasma and serum with reduced co-purification of non-exosomal blood proteins. The optimized protocol includes ultrafiltration, protease treatment, and size exclusion chromatography. Enhanced purification of exosomes benefits downstream analyses, including more accurate quantification of vesicles and proteomic characterization.

Exosomes, a type of nanovesicle released from all cell types, can be isolated from any bodily fluid. The contents of exosomes, including proteins and ...

Rapid Isolation of the Mitoribosome from HEK Cells

The human mitochondria possess a dedicated set of ribosomes (mitoribosomes) that translate 13 essential protein components of the oxidative phosphorylation complexes encoded by the mitochondrial genome. Since all proteins synthesized by human mitoribosomes are integral membrane proteins, human mitoribosomes are tethered to the mitochondrial inner membrane during translation. Compared to the cytosolic ribosome the mitoribosome has a sedimentation coefficient of 55S, half the rRNA content, no 5S rRNA and 36 additional proteins. Therefore, a higher protein-to-RNA ratio and an atypical structure make the human mitoribosome substantially distinct from its cytosolic counterpart.
Despite the central importance of the mitoribosome to life, no protocols were available to purify the intact complex from human cell lines. Traditionally, mitoribosomes were isolated from mitochondria-rich animal tissues that required kilograms of starting material. We reasoned that mitochondria in dividing HEK293-derived human cells grown in nutrient-rich expression medium would have an active mitochondrial translation, and, therefore, could be a suitable source of material for the structural and biochemical studies of the mitoribosome. To investigate its structure, we developed a protocol for large-scale purification of intact mitoribosomes from HEK cells. Herein, we introduce nitrogen cavitation method as a faster, less labor-intensive and more efficient alternative to traditional mechanical shear-based methods for cell lysis. This resulted in preparations of the mitoribosome that allowed for its structural determination to high resolution, revealing the composition of the intact human mitoribosome and its assembly intermediates. Here, we follow up on this work and present an optimized and more cost-effective method requiring only ~1010 cultured HEK cells. The method can be employed to purify human mitoribosomal translating complexes, mutants, quality control assemblies and mitoribosomal subunits intermediates. The purification can be linearly scaled up tenfold if needed, and also applied to other types of cells.

Mitochondria have specialized ribosomes that diverged from their bacterial and cytoplasmic counterparts. Here we show how mitoribosomes can be obtained from their native compartment in HEK cells. The method involves isolation of mitochondria from suspension cells and consequent purification of mitoribosomes.

The human mitochondria possess a dedicated set of ribosomes (mitoribosomes) that translate 13 essential protein components of the oxidative ...

Isolation of Tissue Extracellular Vesicles from the Liver

Extracellular vesicles (EVs) can be released from many different cell types and detected in most, if not all, body fluids. EVs can participate in cell-to-cell communication by shuttling bioactive molecules such as RNA or protein from one cell to another. Most studies of EVs have been performed in cell culture models or in EVs isolated from body fluids. There is emerging interest in the isolation of EVs from tissues to study their contribution to physiological processes and how they are altered in disease. The isolation of EVs with sufficient yield from tissues is technically challenging because of the need for tissue dissociation without cellular damage. This method describes a procedure for the isolation of EVs from mouse liver tissue. The method involves a two-step process starting with in situ collagenase digestion followed by differential ultra-centrifugation. Tissue perfusion using collagenase provides an advantage over mechanical cutting or homogenization of liver tissue due to its increased yield of obtained EVs. The use of this two-step process to isolate EVs from the liver will be useful for the study of tissue EVs.

This is a protocol to isolate tissue extracellular vesicles (EVs) from the liver. The protocol describes a two-step process involving collagenase perfusion followed by differential ultracentrifugation to isolate liver tissue EVs.

Extracellular vesicles (EVs) can be released from many different cell types and detected in most, if not all, body fluids. EVs can participate in ...

Isolation of Lipoprotein Particles from Chicken Egg Yolk for the Study of Bacterial Pathogen Fatty Acid Incorporation into Membrane Phospholipids

Staphylococcus aureus and other Gram-positive pathogens incorporate fatty acids from the environment into membrane phospholipids. During infection, the majority of exogenous fatty acids are present within host lipoprotein particles. Uncertainty remains as to the reservoirs of host fatty acids and the mechanisms by which bacteria extract fatty acids from the lipoprotein particles. In this work, we describe protocols for enrichment of low-density lipoprotein (LDL) particles from chicken egg yolk and determining whether LDLs serve as fatty acid reservoirs for S. aureus. This method exploits unbiased lipidomic analysis and chicken LDLs, an effective and economical model for the exploration of interactions between LDLs and bacteria. The analysis of S. aureus integration of exogenous fatty acids from LDLs is performed using high-resolution/accurate mass spectrometry and tandem mass spectrometry, enabling the characterization of the fatty acid composition of the bacterial membrane and unbiased identification of novel combinations of fatty acids that arise in bacterial membrane lipids upon exposure to LDLs. These advanced mass spectrometry techniques offer an unparalleled perspective of fatty acid incorporation by revealing the specific exogenous fatty acids incorporated into the phospholipids. The methods outlined here are adaptable to the study of other bacterial pathogens and alternative sources of complex fatty acids.

This method provides a framework for studying incorporation of exogenous fatty acids from complex host sources into bacterial membranes, particularly Staphylococcus aureus. To achieve this, protocols for the enrichment of lipoprotein particles from chicken egg yolk and subsequent fatty acid profiling of bacterial phospholipids utilizing mass spectrometry are described.

Staphylococcus aureus and other Gram-positive pathogens incorporate fatty acids from the environment into membrane phospholipids. During infection, the ...

Translating Ribosome Affinity Purification (TRAP) for RNA Isolation from Endothelial Cells In Vivo

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis of transcriptome and gene expression by qPCR and RNA sequencing. Comprehensive transcriptome and gene expression analysis of specific cell types in complex tissues and organs will be critical to understand cellular and molecular mechanisms by which genes are regulated and their association with tissue homeostasis and organ functions. In this article, we demonstrate the methodology for isolation of ribosome-bound RNA directly in vivo in the vascular endothelia of animal lungs as an example. The specific materials and procedures for tissue processing and RNA purification will be described, including the assessment of RNA quality and yield as well as real time qPCR for arteriogenic gene assays. This approach, known as translating ribosome affinity purification (TRAP) technique, can be utilized for characterization of gene expression and transcriptome analysis of certain cell types directly in vivo in any specific type in complex tissues.

Translating Ribosome Affinity Purification TRAP for RNA Isolation from Endothelial Cells In Vivo

We present an approach to purify ribosome-bound mRNA from vascular endothelial cells (ECs) directly in mouse brain, lung and heart tissues via EC-specific genetic tag of enhanced green fluorescence protein (EGFP)in ribosomes in combination with RNA purification.

Many studies have been limited to using in vitro cellular assays and whole tissues or isolating of specific cell types from animals for in vitro analysis ...

In Vitro Drug Screening Against All Life Cycle Stages of Trypanosoma cruzi Using Parasites Expressing &#946;-galactosidase

Trypanosoma cruzi is the causative agent of Chagas disease (ChD), an endemic disease of public health importance in Latin America that also affects many non-endemic countries due to the increase in migration. This disease affects nearly 8 million people, with new cases estimated at 50,000 per year. In the 1960s and 70s, two drugs for ChD treatment were introduced: nifurtimox and benznidazole (BZN). Both are effective in newborns and during the acute phase of the disease but not in the chronic phase, and their use is associated with important side effects. These facts underscore the urgent need to intensify the search for new drugs against T. cruzi.
T. cruzi is transmitted through hematophagous insect vectors of the Reduviidae and Hemiptera families. Once in the mammalian host, it multiplies intracellularly as the non-flagellated amastigote form and differentiates into the trypomastigote, the bloodstream non-replicative infective form. Inside the insect vector, trypomastigotes transform into the epimastigote stage and multiply through binary fission.
This paper describes an assay based on measuring the activity of the cytoplasmic &#946;-galactosidase released into the culture due to parasites lysis by using the substrate, chlorophenol red &#946;-D-galactopyranoside (CPRG). For this, the T. cruzi Dm28c strain was transfected with a &#946;-galactosidase-overexpressing plasmid and used for in vitro pharmacological screening in epimastigote, trypomastigote, and amastigote stages. This paper also describes how to measure the enzymatic activity in cultured epimastigotes, infected Vero cells with amastigotes, and trypomastigotes released from the cultured cells using the reference drug, benznidazole, as an example. This colorimetric assay is easily performed and can be scaled to a high-throughput format and applied to other T. cruzi strains.

In Vitro Drug Screening Against All Life Cycle Stages of Trypanosoma cruzi Using Parasites Expressing &#946;-galactosidase

We describe a high-throughput colorimetric assay measuring &#946;-galactosidase activity in three life cycle stages of Trypanosoma cruzi, the causative agent of Chagas disease. This assay can be used to identify trypanocidal compounds in an easy, fast, and reproducible manner.

Trypanosoma cruzi is the causative agent of Chagas disease (ChD), an endemic disease of public health importance in Latin America that also affects many ...