Name: identification of plant ice-binding proteins through assessment of ice-recrystallization inhibition and isolation using ice-affinity purification
Uploaded: 2017-05-05T13:00:00
Description: Watch this Scientific Journal Video about Identification of Plant Ice-binding Proteins Through Assessment of Ice-recrystallization Inhibition and Isolation Using Ice-affinity Purification at JoVE.com

This work was funded by an NSERC (Canada) grant to VKW.

1. Splat Apparatus Setup
<ol>
	<li>Fill a temperature-programmable circulating water bath with ethylene glycol (50% v/v in water). 
	NOTE: Green automotive ethylene glycol can be used.</li>
	<li>To assemble the external chamber, use insulated plastic tubing to attach the water bath to a double-walled glass bowl. Insulate the glass bowl with polystyrene foam and cover with a plastic petri dish lid. Cut a 3-4 inch hole in the bottom of the polystyrene chamber so that the light source can be seen through the glass ch...

<ol>
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E., Laybourn-Parry, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Demonstration+of+antifreeze+protein+activity+in+Antarctic+lake+bacteria.">Demonstration of antifreeze protein activity in Antarctic lake bacteria.</a> Microbiology. 150 (Pt 1), 171-180 (2004).</li><li>Knight, C. A., Cheng, C. C., DeVries, 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=Adsorption+of+alpha-helical+antifreeze+peptides+on+specific+ice+crystal+surface+planes.">Adsorption of alpha-helical antifreeze peptides on specific ice crystal surface planes.</a> Biophys. L. 59 (20), 409-418 (1991).</li><li>Yeh, Y., Feeney, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antifreeze+proteins:+structures+and+mechanisms+of+function.">Antifreeze proteins: structures and mechanisms of function.</a> Chem. Rev. 96 (2), 601-618 (1996).</li><li>Smolin, N., Daggett, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+ice-like+water+structure+on+the+surface+of+an+antifreeze+protein.">Formation of ice-like water structure on the surface of an antifreeze protein.</a> J. Phys. Chem. B. 112 (19), 6193-6202 (2008).</li><li>Graham, L. A., Davies, P. 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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flies+expand+the+repertoire+of+protein+structures+that+bind+ice.">Flies expand the repertoire of protein structures that bind ice.</a> Proc. Natl. Acad. Sci. U.S.A. 112 (3), 737-742 (2015).</li><li>Guo, S., Garnham, C. P., Whitney, J. C., Graham, L. A., Davies, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Re-evaluation+of+a+Bacterial+Antifreeze+Protein+as+an+Adhesin+with+Ice-Binding+Activity.">Re-evaluation of a Bacterial Antifreeze Protein as an Adhesin with Ice-Binding Activity.</a> PLoS One. 7 (11), e48805 (2012).</li><li>Marshall, C. B., Fletcher, G. L., Davies, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperactive+antifreeze+protein+in+a+fish.">Hyperactive antifreeze protein in a fish.</a> Nature. 429 (6988), 153 (2004).</li><li>Zhang, D. Q., Liu, B., Feng, D. R., He, Y. M., Wang, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression,+purification+and+antifreeze+activity+of+carrot+antifreeze+protein+and+its+mutants.">Expression, purification and antifreeze activity of carrot antifreeze protein and its mutants.</a> Protein Expr. Purif. 35 (2), 257-263 (2007).</li><li>Gupta, R., Dreswal, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+temperature+stress+modulated+secretome+analysis+and+purification+of+antifreeze+protein+from+Hippophae+rhamnoides,+a+Himalayan+wonder+plant.">Low temperature stress modulated secretome analysis and purification of antifreeze protein from Hippophae rhamnoides, a Himalayan wonder plant.</a> Proteome Res. 11 (5), 2684-2696 (2012).</li><li>Kuiper, M. J., Lankin, C., Gauthier, S. Y., Walker, V. K., Davies, P. 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+antifreeze+proteins+by+adsorption+to+ice.">Purification of antifreeze proteins by adsorption to ice.</a> Biochem. Biphys. Res. Commun. 300 (3), 645-648 (2003).</li><li>Middleton, A. 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=Isolation+and+characterization+of+ice-binding+proteins+from+higher+plants.">Isolation and characterization of ice-binding proteins from higher plants.</a> Methods Mol. Biol. 1166, 255-277 (2014).</li><li>Bredow, M., Vanderbeld, B., Walker, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice-binding+proteins+confer+freezing+tolerance+in+transgenic+Arabidopsis+thaliana.">Ice-binding proteins confer freezing tolerance in transgenic Arabidopsis thaliana.</a> Plant Biotechnol. J. , (2016).</li><li>Olijve, L. L., 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=Blocking+rapid+ice+crystal+growth+through+nonbasal+plane+adsorption+of+antifreeze+proteins.">Blocking rapid ice crystal growth through nonbasal plane adsorption of antifreeze proteins.</a> Proc. Natl. Acad. Sci. U.S.A. 113 (14), 3740-3745 (2016).</li><li>Zakharov, B., 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=Ice+Recrystallization+in+a+Solution+of+a+Cryoprotector+and+Its+inhibition+by+a+Protein:+Synchrotron+X-Ray+Diffraction+Study.">Ice Recrystallization in a Solution of a Cryoprotector and Its inhibition by a Protein: Synchrotron X-Ray Diffraction Study.</a> J. Pharm. Sci. 105 (7), 2129-2138 (2016).</li><li>Capicciotti, C. 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=Small+molecule+ice+recrystallization+inhibitors+enable+freezing+of+human+red+blood+cells+with+reduced+glycerol+concentrations.">Small molecule ice recrystallization inhibitors enable freezing of human red blood cells with reduced glycerol concentrations.</a> Sci. Rep. 5, 9692 (2015).</li><li>Knight, C. A., Cheng, C. C., DeVries, 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=Adsorption+of+alpha-helical+antifreeze+peptides+on+specific+ice+crystal+surface+planes.">Adsorption of alpha-helical antifreeze peptides on specific ice crystal surface planes.</a> Biophys. J. 59 (2), 409-418 (1991).</li><li>Van Driessche, E., Beeckmans, S., Dejaegere, R., Kanarek, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thiourea:+the+antioxidant+of+choice+for+the+purification+of+proteins+from+phenol+rich+plant+tissues.">Thiourea: the antioxidant of choice for the purification of proteins from phenol rich plant tissues.</a> Anal. Biochem. 141 (1), 184-188 (1984).</li><li>Marshall, C. J., Basu, K., Davies, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice-shell+purification+of+ice-binding+proteins.">Ice-shell purification of ice-binding proteins.</a> Cryobiology. 72 (3), 258-263 (2016).</li><li>Basu, 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=Determining+the+ice-binding+planes+of+antifreeze+proteins+by+fluorescence-based+ice+plane+affinity.">Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity.</a> J. Vis. Exp. (83), e51185 (2014).</li><li>Sandve, S. R., Rudi, H., Asp, T., Rognli, O. 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For the successful analysis and purification of IBPs, it is important to understand the temperature-sensitive nature of some of these proteins. Certain plant IBPs become unstable at temperatures above 0 &#176;C, resulting in unfolding, precipitation and inactivity. In order to obtain active IBPs, it is often critical that plants are processed in a cold room (~4 &#176;C) and samples are kept on ice during experimentation. Another factor to consider when using whole-cell crude lysates is the degradation of proteins by endo...

Ice-binding proteins (IBPs) are a diverse family of protective proteins that have been discovered in a number of organisms including plants1, insects2, fish3, and microbes4. The key feature of these proteins is their unique ability to specifically and efficiently adsorb to ice crystals, modifying their growth. IBPs have several documented properties, with the two most well characterized being thermal hysteresis (TH) and ice-recrystallization inhibition (IRI). TH activity is more readily observed in IBPs produced in freeze-intolerant animals. This activity results in lowering of the freezing point of organisms&#39; circulatory or interstitial fluids to prevent freezing. In contrast, in freeze-tolerant organisms, which will inevitably freeze at subzero temperatures, IBPs appear to have low TH activity. Despite the low TH activity, a high IRI activity to restrict ice crystal growth is often observed with these proteins. For the freeze-tolerant organism, this IRI activity presumably helps protect cells from the uncontrolled growth of ice in extracellular compartments.
The &#34;mattress button&#34; model can be used to describe the mechanism by which IBPs prevent the growth of ice crystals5. Under this model, IBPs specifically adsorb to the ice crystal surface at intervals, such that water molecules can only incorporate with the growing ice crystal lattice in the space between bound IBPs. This creates a curvature that makes the incorporation of additional water molecules unfavorable, an event that can be described by the Gibbs-Thomson effect6. The anchored clathrate waters hypothesis provides a mechanism for the specific binding of IBPs to the ice crystal surface whereby the presence of charged residues, specifically positioned on the protein ice binding site, results in the reorganization of water molecules so they match one or more planes of the ice crystal lattice7.
TH activity can be quantified by measuring the difference between the melting and freezing temperatures of a single ice crystal in the presence of an IBP. While TH activity is a widely accepted method of evaluating the activity of IBPs, the low TH gap produced by plant IBPs (typically only a fraction of a degree) normally requires a high protein concentration, specialized equipment and operator experience. Although non-IBPs may restrict ice crystal growth, it is a property shared by all IBPs and thus testing for IRI activity is an effective initial screen for the presence of IBPs, especially for those with low TH activity. The methodology used to test this activity is known as a &#39;splat assay&#39;, whereby a protein sample is flash frozen to produce a monolayer of small ice crystals, which are observed over a period of time to determine if ice crystal growth is restricted. Unlike other methods used to screen a source tissue sample for the presence of IBPs, this technique is applicable to low protein concentrations in the range of 10-100 ng, utilizes easily-fabricated equipment, and generates data that is quickly and easily interpreted. However, it is important to stress that this assay provides an initial screen for IBPs that should be followed by the determination of TH and ice crystal shaping.
The isolation of native proteins is challenging, often requiring information regarding the structural and biochemical properties of a protein of interest. The affinity of IBPs for ice allows for the isolation of these proteins using ice as a substrate for purification purposes. Since the majority of molecules are pushed ahead of the ice-water boundary during ice crystal growth, slow growth of an ice-hemisphere in the presence of an IBP sample results in a highly-purified sample, devoid of large quantities of contaminating proteins and solutes. This method has been used to identify IBPs from insects8,9,10, bacteria11, fish12 and plants13,14. Additionally, the IBP-enriched fractions achieved through this method can also be used for downstream biochemical analysis. This paper outlines the identification of IBPs in plants through the induction and extraction of IBPs, analysis of IRI activity to confirm the presence of proteins, and the isolation of proteins using ice affinity purification.

<table border="0" cellpadding="0" cellspacing="0" width="1117">
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1.5 mL microcentrifugetubes</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">05-408-129</td>
			<td style="width:631px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Adjustable lab jack</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">S63080</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Benchtop centrifuge</td>
			<td style="width:152px;">Desaga MC2</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Brass probe</td>
			<td style="width:152px;">Custom built</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Camera/ camera port</td>
			<td style="width:152px;">Canon</td>
			<td style="width:119px;"></td>
			<td>Canon Power Shot SX110 digitial camera; custom built microscope port</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cheesecloth</td>
			<td style="width:152px;">Purewipe/Fisher Scientific</td>
			<td style="width:119px;">06-665-25A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Concentration tubes (0.5 mL)</td>
			<td style="width:152px;">EMD Millipore</td>
			<td style="width:119px;">UFC501008</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Concentration tubes (15 mL)</td>
			<td style="width:152px;">EMD Millipore</td>
			<td style="width:119px;">UFC900308</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Conical tubes (50 mL)</td>
			<td style="width:152px;">Thermo Fisher</td>
			<td style="width:119px;">AM12502</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cooling block</td>
			<td style="width:152px;">VWR</td>
			<td style="width:119px;">13259</td>
			<td>Use a metal heating block</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dehumidifier</td>
			<td style="width:152px;">Whirlpool</td>
			<td style="width:119px;"></td>
			<td>50 pint Energy Star dehumidifier; purchase from local supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dessciation beads</td>
			<td style="width:152px;">t.h.e. Dessicant/VWR</td>
			<td style="width:119px;">EM-DX0017-2</td>
			<td>6-8 mesh size; 100% indicating</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dissection microscope</td>
			<td style="width:152px;">Olympus Tokyo</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Double walled glass bowl</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Purchase from local lab glassware supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dry ice</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Use local supplier; hazardous&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EDTA-protease inhibitor tablets</td>
			<td style="width:152px;">Sigma Aldrich</td>
			<td>11836170001</td>
			<td>Roche cOmplete mini</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethylene glycol</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Green automotive ethylene glycol can be purchased from any local hardware store (i.e. Home Depot)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hexane</td>
			<td style="width:152px;">Sigma Aldrich</td>
			<td style="width:119px;">296090</td>
			<td>Anhydrous, 95%; hazardous</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Immersion oil</td>
			<td style="width:152px;">Sigma Aldrich</td>
			<td style="width:119px;">56822</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">JA10/20 centrifuge</td>
			<td style="width:152px;">Beckman</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Large plastic petri dish</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Liquid nitrogen</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Use local supplier; hazardous&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Magnetic stir plate</td>
			<td style="width:152px;">Hanna Instruments</td>
			<td style="width:119px;">HI190M</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microscope cover slides</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">12-542A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Plastic tube</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Purchase PVC pipe from local hardware store</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Polarized film</td>
			<td style="width:152px;">Edmund Optics</td>
			<td style="width:119px;">43-781</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Polystyrene foam</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td>Can be constructed from polystyrene shipping boxes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Poreclain mortar and pestle</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">FB961</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">PVPP</td>
			<td style="width:152px;">Sigma Aldrich</td>
			<td style="width:119px;">77627</td>
			<td>110 &#181;m particle size</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Retort Stand</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">12-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Small stir bar</td>
			<td style="width:152px;">Fisher</td>
			<td style="width:119px;">14-513-51</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Temperature-programmable water bath</td>
			<td style="width:152px;">VWR</td>
			<td style="width:119px;">13271-118</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Vacuum grease</td>
			<td style="width:152px;">Dow Corning/Sigma Aldrich</td>
			<td style="width:119px;">Z273554</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Vinyl tubing</td>
			<td style="width:152px;">Generic</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
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identification of plant ice-binding proteins through assessment of ice-recrystallization inhibition and isolation using ice-affinity purification

Ice-binding proteins (IBPs) belong to a family of stress-induced proteins that are synthesized by certain organisms exposed to subzero temperatures. In plants, freeze damage occurs when extracellular ice crystals grow, resulting in the rupture of plasma membranes and possible cell death. Adsorption of IBPs to ice crystals restricts further growth by a process known as ice-recrystallization inhibition (IRI), thereby reducing cellular damage. IBPs also demonstrate the ability to depress the freezing point of a solution below the equilibrium melting point, a property known as thermal hysteresis (TH) activity. These protective properties have raised interest in the identification of novel IBPs due to their potential use in industrial, medical and agricultural applications. This paper describes the identification of plant IBPs through 1) the induction and extraction of IBPs in plant tissue, 2) the screening of extracts for IRI activity, and 3) the isolation and purification of IBPs. Following the induction of IBPs by low temperature exposure, extracts are tested for IRI activity using a &#39;splat assay&#39;, which allows the observation of ice crystal growth using a standard light microscope. This assay requires a low protein concentration and generates results that are quickly obtained and easily interpreted, providing an initial screen for ice binding activity. IBPs can then be isolated from contaminating proteins by utilizing the property of IBPs to adsorb to ice, through a technique called &#39;ice-affinity purification&#39;. Using cell lysates collected from plant extracts, an ice hemisphere can be slowly grown on a brass probe. This incorporates IBPs into the crystalline structure of the polycrystalline ice. Requiring no a priori biochemical or structural knowledge of the IBP, this method allows for recovery of active protein. Ice-purified protein fractions can be used for downstream applications including the identification of peptide sequences by mass spectrometry and the biochemical analysis of native proteins.

For ease of set-up, Figure 1 and Figure 2 are included as visual representations of the equipment used for IRI analysis and ice-affinity purification, respectively. Results of IRI analysis using extracts collected from mustard weed with and without IBPs are depicted in Figure 3. These results show that extracts collected from mustard weed, which is not freeze-tolerant, were unable to...

Watch this Scientific Journal Video about Identification of Plant Ice-binding Proteins Through Assessment of Ice-recrystallization Inhibition and Isolation Using Ice-affinity Purification at JoVE.com

Identification of Plant Ice-binding Proteins Through Assessment of Ice-recrystallization Inhibition and Isolation Using Ice-affinity Purification

This paper outlines the identification of ice-binding proteins from freeze-tolerant plants through the assessment of ice-recrystallization inhibition activity and subsequent isolation of native IBPs using ice-affinity purification.

Ice-binding proteins (IBPs) belong to a family of stress-induced proteins that are synthesized by certain organisms exposed to subzero temperatures. In ...

The overall goal of this protocol is to identify novel ice-binding proteins or IBPs from plants by testing for ice-binding activity and isolating native peptides using ice-affinity purification. This method can help answer key questions in the field of plant freeze tolerance, specifically ice-binding proteins. The main advantage of this technique is that it allows you isolate ice-binding proteins from native extracts without the use of complicated purification methods.Visual demonstration of this method is critical, since the apparatus set-up can be difficult to conceptualize. Begin this protocol with splat apparatus setup as described in the text protocol. To induce the expression of ice-binding proteins, or IBPs, in freeze-tolerant grasses or other freeze-tolerant plant species, cold-acclimate plants for up to one week at four degrees Celsius under low light conditions.Obtain approximately 0.1 gram of leaf tissue by cutting at the base of the stem and then placing in a 1.5 milliliter tube. Immediately flash-freeze the sample in liquid nitrogen and store at minus 80 degrees Celsius until use. To lyse the cells, grind the tissue sample into a fine powder using a mortar and pestle under liquid nitrogen.Ensure that the liquid nitrogen does not evaporate during the homogenization process. Immediately place the ground samples on ice and allow the liquid nitrogen to completely evaporate. Then add one milliliter of a native protein extraction buffer and pipette to mix.Gently shake the samples overnight at four degrees Celsius and conduct the remaining steps at the same temperature. The next day, remove cellular debris by centrifuging the samples at approximately 1, 600 times G for five minutes. Retain the soluble fraction and centrifuge for an additional five minutes if cellular debris persists.Clarified samples can be stored at minus 20 degrees Celsius until use. Pour 100 milliliters of hexane into the external chamber set up with the polarized film and add five to six desiccation beads to prevent moisture buildup on the slides. Then add a small amount of vacuum grease to the plate covering the bath and twist to ensure a tight seal and prevent evaporation of the hexane.40 minutes prior to starting the experiment, place the cooling block in a polystyrene box directly below the plastic tube and cover it completely with dry ice. Before beginning the assay, ensure that the tube is level. Then remove the dry ice from the top of the cold block.First, test this procedure with water to determine where on the cooling block the sample will drop. Dip the disposable tip affixed to an automatic pipette in immersion oil, which will allow the sample to fall rather than adhere to the outside of the pipette. Use a paper towel to remove any excess oil.Then aspirate 10 microliters of water. Place the pipette directly over the plastic tubing before releasing the water. A distinct splat sound should be heard when the water hits the cooling block, creating a monolayer of ice crystals.Next, place a glass microscope cover slide on the drop mark that has been determined with water. Immediately before starting the assay, turn on the light source and scrape any ice that has formed on the bottom of the glass chamber. Then perform the splat assay with the sample, as done for the water, releasing 10 microliters of the sample onto the glass cover slide to create a monolayer of ice crystals.Quickly and carefully remove the microscope slide from the cold block using tweezers and place in the hexane bath on top of the polarizing film. Looking under the microscope, put the microscope slide into the field of view and adjust the objective lens so that the cross-polarization allows for the visualization of high-contrast ice crystals. Attach the camera to the microscope and adjust the settings to macro to allow clear visualization of ice crystals and capture the image.Repeat these steps for all samples. Typically place up to six slides with a different sample in the hexane chamber. Once finished, turn off the light source.Then place a plastic plate over the hexane bath, ensuring a tight seal, and allow ice crystals to anneal overnight. Following incubation, capture images of the ice films as before. After cold-acclimating the plant tissue as before, collect approximately 100 to 150 grams of the ground biomass in 20-milliliter tubes.Immediately flash-freeze the samples, and keep them at minus 80 degrees Celsius before use. Prepare the sample as before, using a one-to-one ratio for re-suspension of the leaf tissue. Use additional protease inhibitor tablets to avoid the degradation of IBPs by endogenous proteases.To remove cellular debris, sift the lysate through two layers of cheesecloth three times. Pellet the debris by centrifugation at 30, 000 times G for 40 minutes at four degrees Celsius. Then increase the volume of sample to 120 milliliters using native protein extraction buffer and use the lysade immediately for ice-affinity purification to avoid any loss of ice-binding activity.After cooling the ice finger to minus 0.5 degrees Celsius, subsequently submerse it into a 50-milliliter tube containing cold distilled water. Add a few ice chips to facilitate ice nucleation and allow a thin layer of ice to form on the finger. This process typically takes between 20 and 30 minutes.Place the sample in a 150-milliliter glass beaker containing a small magnetic stir bar, which is placed in a polystyrene container on top of the magnetic stirrer. Make sure that the ice finger is centered and lowered at least halfway into the liquid sample. Then seal the container.Allow the program to run for approximately two days, checking every 24 hours. Once 50%of the sample is frozen, stop the program. Incorporation of IBPs into the ice hemisphere will result in ice etching.To remove the ice hemisphere, warm the probe to four degrees Celsius. Then rinse the hemisphere with distilled water to remove unbound protein and thaw at four degrees Celsius. If the ice hemisphere still contains pigment, or to increase the sample purification, repeat the purification steps two to three times.Shown here are extracts collected from a buffer control lacking IBPs and extracts from wild-type Arabidopsis thaliana that do not contain IBPs. After 18 hours, the buffer control and A.thaliana extracts are unable to restrict ice crystal growth. In contrast, the small ice crystals seen with extracts of transgenic A.thaliana expressing IBPs from cold-acclimated Lolium perenne restrict ice crystal growth substantially.After the first round of purification, the high degree of ice etching on the hemisphere surface indicates that IBPs have adsorped to the ice and modified growth of the ice crystals. To remove additional solutes, pigments, and contaminating proteins, a second round of ice-affinity was used, resulting in a clearer ice hemisphere. Following this procedure, ice shaping and thermal hysteresis can be evaluated using a nanoliter osmometer in order to further characterize ice-binding proteins.Additionally, isolated fractions can be sent for mass spectometry in order to identify the peptide sequences.

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Research

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Biochemistry

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 ...

2 in 1: One-step Affinity Purification for the Parallel Analysis of Protein-Protein and Protein-Metabolite Complexes

Cellular processes are regulated by interactions between biological molecules such as proteins, metabolites, and nucleic acids. While the investigation of protein-protein interactions (PPI) is no novelty, experimental approaches aiming to characterize endogenous protein-metabolite interactions (PMI) constitute a rather recent development. Herein, we present a protocol that allows simultaneous characterization of the PPI and PMI of a protein of choice, referred to as bait. Our protocol was optimized for Arabidopsis cell cultures and combines affinity purification (AP) with mass spectrometry (MS)-based protein and metabolite detection. In short, transgenic Arabidopsis lines, expressing bait protein fused to an affinity tag, are first lysed to obtain a native cellular extract. Anti-tag antibodies are used to pull down protein and metabolite partners of the bait protein. The affinity-purified complexes are extracted using a one-step methyl tert-butyl ether (MTBE)/methanol/water method. Whilst metabolites separate into either the polar or the hydrophobic phase, proteins can be found in the pellet. Both metabolites and proteins are then analyzed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS or UPLC-MS/MS). Empty-vector (EV) control lines are used to exclude false positives. The major advantage of our protocol is that it enables identification of protein and metabolite partners of a target protein in parallel in near-physiological conditions (cellular lysate). The presented method is straightforward, fast, and can be easily adapted to biological systems other than plant cell cultures.

Protein-protein and protein-metabolite interactions are crucial for all cellular functions. Herein, we describe a protocol that allows parallel analysis of these interactions with a protein of choice. Our protocol was optimized for plant cell cultures and combines affinity purification with mass spectrometry-based protein and metabolite detection.

Cellular processes are regulated by interactions between biological molecules such as proteins, metabolites, and nucleic acids. While the investigation of ...

Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition

Oxygen-sensitive proteins, including those enzymes which utilize oxygen as a substrate, can have reduced stability when purified using traditional aerobic purification methods. This manuscript illustrates the technical details involved in the anaerobic purification process, including the preparation of buffers and reagents, the methods for column chromatography in a glove box, and the desalting of the protein prior to kinetics. Also described are the methods for preparing and using an oxygen electrode to perform kinetic characterization of an oxygen-utilizing enzyme. These methods are illustrated using the dioxygenase enzyme DesB, a gallate dioxygenase from the bacterium Sphingobium sp. strain SYK-6.

Here we present a protocol for anaerobic protein purification, anaerobic protein concentration, and subsequent kinetic characterization using an oxygen electrode system. The method is illustrated using the enzyme DesB, a dioxygenase enzyme which is more stable and active when purified and stored in an anaerobic environment.

Oxygen-sensitive proteins, including those enzymes which utilize oxygen as a substrate, can have reduced stability when purified using traditional aerobic ...

Affinity Purification of Chloroplast Translocon Protein Complexes Using the TAP Tag

Chloroplast biogenesis requires the import of thousands of nucleus-encoded proteins into the plastid. The import of these proteins depends on the translocon at the outer (TOC) and inner (TIC) chloroplast membranes. The TOC and TIC complexes are multimeric and probably contain yet unknown components. One of the main goals in the field is to establish the complete inventory of TOC and TIC components. For the isolation of TOC-TIC complexes and the identification of new components, the preprotein receptor TOC159 has been modified N-terminally by the addition of the tandem affinity purification (TAP) tag resulting in TAP-TOC159. The TAP-tag is designed for two sequential affinity purification steps (hence "tandem affinity"). The TAP-tag used in these studies consists of a N-terminal IgG-binding domain derived from Staphylococcus aureus Protein A (ProtA) followed by a calmodulin-binding peptide (CBP). Between these two affinity tags, a tobacco etch virus (TEV) protease cleavage site has been included. Therefore, TEV protease can be used for gentle elution of TOC159-containing complexes after binding to IgG beads. In the protocol presented here, the second Calmodulin-affinity purification step was omitted. The purification protocol starts with the preparation and solubilization of total cellular membranes. After the detergent-treatment, the solubilized membrane proteins are incubated with IgG beads for the immunoisolation of TAP-TOC159-containing complexes. Upon binding and extensive washing, TAP-TOC159 containing complexes are cleaved and released from the IgG beads using the TEV protease whereby the S. aureus IgG-binding domain is removed. Western blotting of the isolated TOC159-containing complexes can be used to confirm the presence of known or suspected TOC and TIC proteins. More importantly, the TOC159-containing complexes have been used successfully to identify new components of the TOC and TIC complexes by mass spectrometry. The protocol that we present potentially allows the efficient isolation of any membrane-bound protein complex to be used for the identification of yet unknown components by mass spectrometry.

We here present a proven and tested protocol for the purification of chloroplast protein import complexes (TOC-TIC complex) using the TAP-tag. The one-step affinity-isolation protocol can potentially be applied to any protein and be used to identify new interaction partners by mass spectrometry.

Chloroplast biogenesis requires the import of thousands of nucleus-encoded proteins into the plastid. The import of these proteins depends on the ...

Capture and Identification of RNA-binding Proteins by Using Click Chemistry-assisted RNA-interactome Capture (CARIC) Strategy

A comprehensive identification of RNA-binding proteins (RBPs) is key to understanding the posttranscriptional regulatory network in cells. A widely used strategy for RBP capture exploits the polyadenylation [poly(A)] of target RNAs, which mostly occurs on eukaryotic mature mRNAs, leaving most binding proteins of non-poly(A) RNAs unidentified. Here we describe the detailed procedures of a recently reported method termed click chemistry-assisted RNA-interactome capture (CARIC), which enables the transcriptome-wide capture of both poly(A) and non-poly(A) RBPs by combining the metabolic labeling of RNAs, in vivo UV cross-linking, and bioorthogonal tagging.

Capture and Identification of RNA-binding Proteins by Using Click Chemistry-assisted RNA-interactome Capture CARIC Strategy

A detailed protocol for applying the click chemistry-assisted RNA-interactome capture (CARIC) strategy to identify proteins binding to both coding and noncoding RNAs is presented.

A comprehensive identification of RNA-binding proteins (RBPs) is key to understanding the posttranscriptional regulatory network in cells. A widely used ...

Identification of Functional Protein Regions Through Chimeric Protein Construction

The goal of this protocol encompasses the design of chimeric proteins in which distinct regions of a protein are replaced by their corresponding sequences in a structurally similar protein, in order to determine the functional importance of these regions. Such chimeras are generated by means of a nested PCR protocol using overlapping DNA fragments and adequately designed primers, followed by their expression within a mammalian system to ensure native secondary structure and post-translational modifications. 
The functional role of a distinct region is then indicated by a loss of activity of the chimera in an appropriate readout assay. In consequence, regions harboring a set of critical amino acids are identified, which can be further screened by complementary techniques (e.g. site-directed mutagenesis) to increase molecular resolution. Although limited to cases in which a structurally related protein with differing functions can be found, chimeric proteins have been successfully employed to identify critical binding regions in proteins such as cytokines and cytokine receptors. This method is particularly suitable in cases in which the protein's functional regions are not well defined, and constitutes a valuable first step in directed evolution approaches to narrow down the regions of interest and reduce the screening effort involved.

Structurally related proteins frequently exert distinct biological functions. The exchange of equivalent regions of these proteins in order to create chimeric proteins constitutes an innovative approach to identify critical protein regions that are responsible for their functional divergence.

The goal of this protocol encompasses the design of chimeric proteins in which distinct regions of a protein are replaced by their corresponding sequences ...

Looking Outwards: Isolation of Cyanobacterial Released Carbohydrate Polymers and Proteins

Cyanobacteria can actively secrete a wide range of biomolecules into the extracellular environment, such as heteropolysaccharides and proteins. The identification and characterization of these biomolecules can improve knowledge about their secretion pathways and help to manipulate them. Furthermore, some of these biomolecules are also interesting in terms of biotechnological applications. Described here are two protocols for easy and rapid isolation of cyanobacterial released carbohydrate polymers and proteins. The method for isolation of released carbohydrate polymers is based on conventional precipitation techniques of polysaccharides in aqueous solutions using organic solvents. This method preserves the characteristics of the polymer and simultaneously avoids the presence of contaminants from cell debris and culture medium. At the end of the process, the lyophilized polymer is ready to be used or characterized or can be subjected to further rounds of purification, depending on the final intended use. Regarding the isolation of the cyanobacterial exoproteome, the technique is based on the concentration of the cell-free medium after removal of the major contaminants by centrifugation and filtration. This strategy allows for reliable isolation of proteins that reach the extracellular milieu via membrane transporters or outer membrane vesicles. These proteins can be subsequently identified using standard mass spectrometry techniques. The protocols presented here can be applied not only to a wide range of cyanobacteria, but also to other bacterial strains. Furthermore, these procedures can be easily tailored according to the final use of the products, purity degree required, and bacterial strain.

Here, protocols for the isolation of cyanobacterial released carbohydrate polymers and isolation of their exoproteomes are described. Both procedures embody key steps to obtain polymers or proteins with high purity degrees that can be used for further analysis or applications. They can also be easily adapted according to specific user needs.

Cyanobacteria can actively secrete a wide range of biomolecules into the extracellular environment, such as heteropolysaccharides and proteins. The ...

Expression, Purification, Crystallization, and Enzyme Assays of Fumarylacetoacetate Hydrolase Domain-Containing Proteins

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this superfamily generally display multi-functionality, involving mainly hydrolase and decarboxylase mechanisms. This article presents a series of consecutive methods for the expression and purification of FAHD proteins, mainly FAHD protein 1 (FAHD1) orthologues among species (human, mouse, nematodes, plants, etc.). Covered methods are protein expression in E. coli, affinity chromatography, ion exchange chromatography, preparative and analytical gel filtration, crystallization, X-ray diffraction, and photometric assays. Concentrated protein of high levels of purity (&#62;98%) may be employed for crystallization or antibody production. Proteins of similar or lower quality may be employed in enzyme assays or used as antigens in detection systems (Western-Blot, ELISA). In the discussion of this work, the identified enzymatic mechanisms of FAHD1 are outlined to describe its hydrolase and decarboxylase bi-functionality in more detail.

Expression and purification of fumarylacetoacetate hydrolase domain-containing proteins is described with examples (expression in E. coli, FPLC). Purified proteins are used for crystallization and antibody production and employed for enzyme assays. Selected photometric assays are presented to display the multi-functionality of FAHD1 as oxaloacetate decarboxylase and acylpyruvate hydrolase.

Fumarylacetoacetate hydrolase (FAH) domain-containing proteins (FAHD) are identified members of the FAH superfamily in eukaryotes. Enzymes of this ...

A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products

Diterpenoids form a diverse class of small molecule natural products that are widely distributed across the kingdoms of life and have critical biological functions in developmental processes, interorganismal interactions, and environmental adaptation. Due to these various bioactivities, many diterpenoids are also of economic importance as pharmaceuticals, food additives, biofuels, and other bioproducts. Advanced genomics and biochemical approaches have enabled a rapid increase in the knowledge of diterpenoid-metabolic genes, enzymes, and pathways. However, the structural complexity of diterpenoids and the narrow taxonomic distribution of individual compounds in often only a single species remain constraining factors for their efficient production. Availability of a broader range of metabolic enzymes now provide resources for producing diterpenoids in sufficient titers and purity to facilitate a deeper investigation of this important metabolite group. Drawing on established tools for microbial and plant-based enzyme co-expression, we present an easily operated and customizable protocol for the enzymatic production of diterpenoids in either Escherichia coli or Nicotiana benthamiana, and the purification of desired products via silica chromatography and semi-preparative HPLC. Using the group of maize (Zea mays) dolabralexin diterpenoids as an example, we highlight how modular combinations of diterpene synthase (diTPS) and cytochrome P450 monooxygenase (P450) enzymes can be used to generate different diterpenoid scaffolds. Purified compounds can be used in various downstream applications, such as metabolite structural analyses, enzyme structure-function studies, and in vitro and in planta bioactivity experiments.

Here we present easy to use protocols for producing and purifying diterpenoid metabolites through the combinatorial expression of biosynthetic enzymes in Escherichia coli or Nicotiana benthamiana, followed by chromatographic product purification. The resulting metabolites are suitable for various studies including molecular structure characterization, enzyme functional studies, and bioactivity assays.

Diterpenoids form a diverse class of small molecule natural products that are widely distributed across the kingdoms of life and have critical biological ...

Transverse Sectioning of Mature Rice (Oryza sativa L.) Kernels for Scanning Electron Microscopy Imaging Using Pipette Tips as Immobilization Support

Starch granules (SGs) exhibit different morphologies depending on the plant species, especially in the endosperm of the Poaceae family. Endosperm phenotyping can be used to classify genotypes based on SG morphotype using scanning electron microscopic (SEM) analysis. SGs can be visualized using SEM by slicing through the kernel (pericarp, aleurone layers, and endosperm) and exposing the organellar contents. Current methods require the rice kernel to be embedded in plastic resin and sectioned using a microtome or embedded in a truncated pipette tip and sectioned by hand using a razor blade. The former method requires specialized equipment and is time-consuming, while the latter introduces a new host of problems depending on rice genotype. Chalky rice varieties, particularly, pose a problem for this type of sectioning due to the friable nature of their endosperm tissue. Presented here is a technique for preparing translucent and chalky rice kernel sections for microscopy, requiring only pipette tips and a scalpel blade. Preparing the sections within the confines of a pipette tip prevents rice kernel endosperm from shattering (for translucent or &#8216;vitreous&#8217; phenotypes) and crumbling (for chalky phenotypes). Using this technique, endosperm cell patterning and the structure of intact SGs can be observed.

Transverse Sectioning of Mature Rice Oryza sativa L. Kernels for Scanning Electron Microscopy Imaging Using Pipette Tips as Immobilization Support

This protocol allows for the preparation of transverse sections of cereal seeds (e.g., rice) for the analysis of endosperm and starch granule morphology using scanning electron microscopy.