1. Plasmidkonstruktion <ol><li> Konstruieren eines Expressionsplasmids (pBAD-HerFab-L177TAG) , die das Ziel - Antikörper - Gen (pBAD-HerFab-WT) mit einem His 6 -tag zum Ausdruck bringen würde, und ersetzen Sie das Codon für Leucin-177 mit dem Amber - Codon (TAG) 27, unter Verwendung von herkömmliche ortsspezifische Mutagenese-Technik. Siehe Tabelle der Materialien. </li><li> Konstruieren Sie ein anderes Expressionsplasmid (pEVOL-AFRS) , um die Gene für die entwickelte tRNA Tyr und Aminoacyl-tRNA - Synthetase (aaRS) Paar enthält. Verwenden Sie die speziell entwickelten Plasmidvektor, pEVOL, für einen effizienten Einbau von UAAs. Die detaillierten Informationen Plasmid und das Klonen Protokolle werden im vorherigen Bericht beschrieben. 28 </li><li> Erhalten Sie qualitativ hochwertige Plasmid-DNA durch kommerziell erhältliche Plasmid Vorbereitungs-Kits verwenden. Das 260/280 Verhältnis von ~ 1,8 ist optimal für die gereinigte DNA. Bei Bedarf durchführen 1% Agarose-Gelelektrophorese, die Reinheit der DNA zu überprüfen. </li></ol><ol><li> Elektroporation <ol><li> Fügen Sie jede 1 &amp; mgr; l DNA von pEVOL-AFRS 28 und pBAD-HerFab-L177TAG bis 20 &amp; mgr; l Escherichia coli DH10β Stamm. Vorsichtig mischen, mit einer Pipette. Die Plasmide können zusammen oder in unabhängigen Reaktionen umgewandelt werden. </li><li> Für 0,1 cm Küvetten, stellen Sie die Elektroporation Einstellungen bis 25 uF und 2,5 kV. </li><li> Setzen Sie die Küvette in die Folie von der schockierenden Kammer. Schieben Sie den Schlitten in die Kammer, bis die Küvette einen festen Kontakt mit den Kammerelektroden macht. </li><li> Pulse einmal durch den Puls-Taste, bis die Elektroporation Gerät einen Signalton drücken. </li><li> 1 ml SOB-Medium mit Katabolitrepression (SOC) Medium , enthaltend 2% (w / v) Trypton, 0,5% (w / v) Hefeextrakt, 10 mM NaCl, 2,5 mM KCl, 10 mM MgCl 2 und 20 mM Glucose in die Küvette um die Mischung in ein Reagenzglas schnell und übertragen. Inkubieren der Zellen für 1 h bei 37 ° C unter Schütteln.</li><li> Spread transformierte E. coli - Zellen auf LB-Medium (LB) Agarplatten , die entsprechenden Antibiotika (35 ug / ml Chloramphenicol und 100 ug / ml Ampicillin zur Selektion pEVOL-AFRS und pBAD-HerFab-L177TAG, respectively). Inkubiere die Platten bei 37 ° C für 12 h. </li></ol></li><li> Kultur Vorbereitung <ol><li> Impfen eine einzelne transformierte Kolonie in 5 ml LB-Medium mit Antibiotika. Inkubieren für 12 h bei 37 ° C unter Schütteln. </li></ol></li></ol> 3. Expression und Reinigung von HerFab-L177AF <ol><li> Die Expression von HerFab-L177AF <ol><li> Übertragung der Primärkultur (5 ml) in 200 ml LB-Medium, das Ampicillin (100 ug / ml) und AF (1 mM), gefolgt von Inkubation bei 37 ° C unter Schütteln. HINWEIS: 100 mM AF-Stammlösung (10 ml) wurde durch Auflösen von 206 mg AF in 100 mM Salzsäure (10 ml, Endvolumen) hergestellt. </li><li> In 2 ml 1,6 M Arabinose (16mM Endkonzentration) , wenn die Kultur der log-Phase erreicht (OD 550 = 0,8, OD = optische Dichte). Inkubieren für 12 h bei 30 ° C unter Schütteln. </li><li> Ernte die Zellen durch Zentrifugieren bei 11.000 xg für 5 min. Überstand verwerfen und gefrier das Pellet bei -20 ° C. </li></ol></li><li> Zelllyse <ol><li> die Mischung 1 h bei 37 ° C Resuspendieren der Zellpellets in 20 ml Puffer periplasmatischen Lyse, enthaltend 30 mM Tris (pH 8,0), 1 mM EDTA, 20% Sucrose und 0,2 mg / ml Lysozym und inkubieren. </li><li> Zentrifugieren Sie das Zelllysat bei 18.000 × g bei 4 ° C für 15 min. Den Überstand in ein frisches Röhrchen und verwerfen das Pellet. </li></ol></li><li> Ni-NTA - Affinitätschromatographie <ol><li> Hinzufügen Ni-NTA-Harz Suspension zu jedem Zentrifugenröhrchen (400 &amp; mgr; l Harz für eine 200 ml-Kultur) und vorsichtig mischen bei 4 ° C für 1 h. </li><li> Gießen Sie die Suspension in eine Polypropylensäule und wäscht das Harz dreimal mit 5 ml Wasch buffer enthaltend 50 mM NaH 2 PO 4 (pH 8,0), 20 mM Imidazol und 300 mM NaCl. </li><li> Eluieren des Zielantikörpers mit 300 &amp; mgr; l Elutionspuffer, der 50 mM NaH 2 PO 4 (pH 8,0), 250 mM Imidazol und 300 mM NaCl. </li><li> Bestimmen Konzentration des mutierten Proteins durch Bradford-Test 29 oder durch die Absorption bei 280 nm gemessen wird . Berechnen Sie den Extinktionskoeffizienten (75.866 M -1 cm -1) für HerFab-L177AF bei 280 nm durch Protein - Extinktionskoeffizient Rechner unter Verwendung des Extinktionskoeffizienten (2471 M -1 cm -1) für AF. HINWEIS: Die Aminosäuresequenz von HerFab kann in der NCBI-Website (: 783.282.791 und GI: 783282792 GI) zu finden. </li></ol></li></ol> 4. Konjugation von Purified HerFab-L177AF mit Alkin-Sonden mit Dehnungs geförderten Azid-Alkin-Cyclo (SPAAC) <ol><li> Geben Sie 20 &amp; mgr; l Cy5.5-Azadibenzocyclooctyne (Cy5.5-ADIBO) in H 2 O (20081; M Endkonzentration) wurde zu einer Lösung von 10 &amp; mgr; l-HerFab L177AF (10 uM Endkonzentration) in Phosphatpuffer 10 mM Na 2 HPO 4 (pH 7,0) und 100 mM NaCl enthält. HINWEIS: Als Alternativen difluoriert Cyclooctin (DIFO) und Bicyclo [6.1.0] Nonin (BCN) Derivate sind für die gleiche Anwendung ebenfalls zur Verfügung. </li><li> Lassen Sie die dehnungs gefördert Cycloadditionsreaktion für 6 h bei 37 ° C fortzufahren. Wenn eine lichtempfindliche Sonde (zB Cy5.5) verwendet wird, umfassen das Reaktionsgefäß mit einer Aluminiumfolie. </li><li> Man reinige den markierten HerFab gemäß Schritt 5. </li></ol> 5. Reinigung von Beschriftete HerFab <ol><li> Fügen 500 ul Probe einem Zentrifugalfilter Spinsäule. </li><li> Zentrifugieren Sie die Spin-Säule bei 14.000 × g bei 4 ° C für 15 min. </li><li> Durchfluss verwerfen und Transferprobe aus dem Spin-Säule in ein 1,5 ml Mikrozentrifugenröhrchen gereinigt. </li><li> Als Alternative 5.1- 5.3 zu Schritt, führen Purification durch Dialyse gegen den gleichen Puffer. </li><li> Lagern Sie die gereinigte markierte HerFab bei 4 ° C. </li></ol> 6. SDS-PAGE-Analyse von Beschriftete HerFab <ol><li> Werden 5 &amp; mgr; l LDS Proteinprobenpuffer mit 106 mM Tris · HCl, 141 mM Tris-Base (pH 8,5), 2% LDS, 10% Glycerol, 0,51 mM EDTA, 0,22 mM SERVA Blau G250 und 0,175 mM Phenolrot bis 13 &amp; mgr; l (-) von 2 &amp; mgr; l Dithiothreitol (DTT, 100 mM Endkonzentration) HerFab (7,8 uM bzw. 0,38 mg / ml) in Gegenwart (+) oder Abwesenheit markierter gereinigt. Inkubieren der Mischung bei 95 ° C für 10 min. </li><li> Bringen Sie die 4-12% Bis-Tris SDS-PAGE-Gel-Kassette in die Elektrophorese-Zelle und fügen Puffer läuft. Laden Sie die konjugierte Proteinproben und die vorgefärbten Molekulargewichtsmarker. Führen Gelelektrophorese für 35 min bei 200 V. Hinweis: Halten Sie die Elektrophorese-Zelle im Dunkeln während des gesamten Zeitraums Photobleaching des Fluorophors zu minimieren. </li><li> Nach der Elektrophorese übertragendas Gel mit einem Fluoreszenz-Gel-Scanners und Scannen für die Fluoreszenzemission bei der entsprechenden Wellenlänge. Für Cy5.5, verwenden Sie die Cy5-Modus in der Scanner-Software. </li><li> Beflecken das Gel mit einem handelsüblichen Proteinfleck. </li></ol>

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The authors have nothing to disclose.

Die genetische Einbau unnatürlicher Aminosäuren in Proteine ​​hat mehrere Vorteile gegenüber anderen Verfahren zur Proteinmodifikation verwendet. 1-3 Einer der wichtigen Vorteile ist die allgemeine Anwendbarkeit auf jede Art von Protein. Im Prinzip gibt es keine Begrenzung für ein Zielprotein und eine Zielstelle des Proteins in der Auswahl. Jedoch Ersetzen eines strukturell oder funktionell wichtigen Rückstand mit einem UAA resultieren, die die Struktur und Funktion des Zielproteins in verändern. Im...

Da der genetische Einbau von p -methoxyphenylalanine in Escherichia coli wurde berichtet, 1 mehr als 100 unnatürliche Aminosäuren (UAAs) wurden in verschiedene Proteine erfolgreich eingebaut. 1-3 Unter diesen UAAs die Aminosäuren bioorthogonale funktionellen Gruppen wurden intensiv untersucht und stellen den größten Anteil enthält. Die bioorthogonale funktionellen Gruppen in den UAAs verwendet werden , umfassen Ketone, 4 Azid, 5 Alkin, 6 Cyclooctin, 7 Tetrazin, 8 α, β-ungesättigten Amids, 9 Norbonen, 10 transcyclooctene, 11 und Bicyclo [6.1.0] -nonyne. 11 Obwohl jede funktionelle Gruppe ihre Vor- und Nachteile hat, die azidhaltigen Aminosäuren am intensivsten wurden für die Protein Konjugation verwendet. p -Azidophenylalanine (AF), eine der Azido-enthaltenden Aminosäuren, ist leicht verfügbar, und ihre Inkorporation efficiency ist ausgezeichnet. Mutant Proteine ​​diese Aminosäure enthalten, können mit Alkinen durch Kupfer-katalysierte Cyclo oder mit Cyclooctenen von SPAAC umgesetzt werden. 12-20 In letzter Zeit wurden Biopharmazeutika große Aufmerksamkeit in der pharmazeutischen Industrie zu gewinnen. Der Antikörper-Arzneimittel - Konjugat (ADC) ist eine Klasse von therapeutischen Antikörpern , die aufgrund ihrer Fähigkeit zur gezielten Therapie für die Behandlung von menschlichen Krebserkrankungen 21 vorteilhaft sind und anderen Krankheiten. Mehr als 50 ADCs sind derzeit in klinischen Studien, und die Zahl steigt schnell. In Entwicklung von ADCs, müssen viele Faktoren berücksichtigt werden, um die Wirksamkeit zu maximieren und die Nebenwirkungen zu minimieren. Unter diesen Faktoren eine effiziente und stellenspezifische Konjugationsreaktion zu einer kovalenten Bindung zwischen einem Antikörper bilden, und ein Medikament ist kritisch. Die gewünschte Effizienz und Spezifität in der Konjugationsreaktion kann in eine durch Konjugation mit einem bioorthogonale funktionelle Gruppe erreicht werden,unnatürliche Aminosäure, die in einem Antikörper, der spezifisch eingeschlossen ist. Hier 22-26 berichten wir über ein Protokoll zur ortsspezifisch integrieren AF in einem Antikörper-Fragment und konjugieren das mutierte Antikörperfragment mit einer biochemischen Sonde.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1. plasmid Construction</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>plasmid pBAD_HerFab_L177TAG</td>
			<td></td>
			<td></td>
			<td>optionally contain the amber stop codon(TAG) at a desired position. Ko, W. et al. Efficient and Site-Specific Antibody Labeling by Strain-promoted Azide-Alkyne Cycloaddition. BKCS. 36 (9), 2352-2354, doi: 10.1002/bkcs.10423, (2015)</td>
		</tr>
		<tr>
			<td>plasmid pEvol-AFRS</td>
			<td></td>
			<td></td>
			<td>Young, T. S., Ahmad, I., Yin, J. A., and Schultz, P. G. An enhanced system for unnatural amino acid mutagenesis in E. coli. J. Mol. Biol. 395 (2), 361-374, doi: 10.1016/j.jmb.2009.10.030, (2010)</td>
		</tr>
		<tr>
			<td>DH10B</td>
			<td>Invitrogen</td>
			<td>C6400-03</td>
			<td>Expression Host</td>
		</tr>
		<tr>
			<td>Plasmid Mini-prep kit</td>
			<td>Nucleogen</td>
			<td>5112</td>
			<td>200/pack</td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Intron biotechnology</td>
			<td>32034</td>
			<td>500g</td>
		</tr>
		<tr>
			<td>Ethidium bromide</td>
			<td>Alfa Aesar</td>
			<td>L07482</td>
			<td>1g</td>
		</tr>
		<tr>
			<td>LB Broth</td>
			<td>BD Difco</td>
			<td>244620</td>
			<td>500g</td>
		</tr>
		<tr>
			<td>2. Culture preparation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2.1) Electroporation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro pulser&#160;</td>
			<td>BIO-RAD</td>
			<td>165-2100</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro pulser cuvette</td>
			<td>BIO-RAD</td>
			<td>165-2089</td>
			<td>0.1cm electrode gap, pkg. of 50</td>
		</tr>
		<tr>
			<td>Ampicillin Sodium</td>
			<td>Wako</td>
			<td>018-10372</td>
			<td>25g</td>
		</tr>
		<tr>
			<td>Chloramphenicol</td>
			<td>Alfa Aesar</td>
			<td>B20841</td>
			<td>25g</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>SAMCHUN</td>
			<td>214230</td>
			<td>500g</td>
		</tr>
		<tr>
			<td>SOC medium</td>
			<td>Sigma</td>
			<td>S1797</td>
			<td>100ML</td>
		</tr>
		<tr>
			<td>3. Expression and purification of HerFab-L177AF</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3.1 Expression of Herfab-L177AF</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>p-azido-L-phenylalanine (AF)</td>
			<td>Bachem</td>
			<td>F-3075.0001</td>
			<td>1g</td>
		</tr>
		<tr>
			<td>L(+)-Arabinose, 99%</td>
			<td>Acros</td>
			<td>104981000</td>
			<td>100g</td>
		</tr>
		<tr>
			<td>Hydrochloric acid, 35~37%</td>
			<td>SAMCHUN</td>
			<td>H0256</td>
			<td>500ml</td>
		</tr>
		<tr>
			<td>3.2 Cell lysis</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tris(hydroxymethyl)aminomethane, 99%</td>
			<td>SAMCHUN</td>
			<td>T1351</td>
			<td>500g</td>
		</tr>
		<tr>
			<td>EDTA disodium salt dihydrate, 99.5%</td>
			<td>SAMCHUN</td>
			<td>E0064</td>
			<td>1kg</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma</td>
			<td>S9378</td>
			<td>500g</td>
		</tr>
		<tr>
			<td>Lysozyme</td>
			<td>Siyaku</td>
			<td>126-0671</td>
			<td>1g</td>
		</tr>
		<tr>
			<td>3.3 Ni-NTA Affinity Chromatography</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ni-NTA resin</td>
			<td>QIAGEN</td>
			<td>30210</td>
			<td>25ml</td>
		</tr>
		<tr>
			<td>Polypropylene column</td>
			<td>QIAGEN</td>
			<td>34924</td>
			<td>50/pack, 1ml capacity</td>
		</tr>
		<tr>
			<td>Imidazole, 99%</td>
			<td>SAMCHUN</td>
			<td>I0578</td>
			<td>1kg</td>
		</tr>
		<tr>
			<td>Sodium phosphate monobasic, 98%</td>
			<td>SAMCHUN</td>
			<td>S0919</td>
			<td>1kg</td>
		</tr>
		<tr>
			<td>Sodium Chloride, 99%</td>
			<td>SAMCHUN</td>
			<td>S2907</td>
			<td>1kg</td>
		</tr>
		<tr>
			<td>4. Conjugation of Purified HerFab-L177AF with Alkyne Probes Using Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC)&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cy5.5-ADIBO&#160;</td>
			<td>FutureChem</td>
			<td>FC-6119</td>
			<td>1mg</td>
		</tr>
		<tr>
			<td>5. Purification of Labeled HerFab</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amicon Ultra 0.5 mL Centrifugal Filters</td>
			<td>MILLIPORE</td>
			<td>UFC500396</td>
			<td>96/pack, 500ul capacity</td>
		</tr>
		<tr>
			<td>6. SDS-PAGE Analysis of Labeled HerFab and Fluorescent Gel Scanning</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1,4-Dithio-DL-threitol, DTT, 99.5 %</td>
			<td>Sigma</td>
			<td>10708984001</td>
			<td>10g</td>
		</tr>
		<tr>
			<td>NuPAGE LDS Sample Buffer, 4X</td>
			<td>Thermofisher</td>
			<td>NP0007</td>
			<td>10ml</td>
		</tr>
		<tr>
			<td>MES running buffer</td>
			<td>Thermofisher</td>
			<td>NP0002</td>
			<td>500ml</td>
		</tr>
		<tr>
			<td>Nupage Novex 4-12% SDS PAGE gels</td>
			<td>Thermofisher</td>
			<td>NO0321</td>
			<td>12well</td>
		</tr>
		<tr>
			<td>Coomassie Brilliant Blue R-250</td>
			<td>Wako</td>
			<td>031-17922</td>
			<td>25g</td>
		</tr>
		<tr>
			<td>Typhoon 9210 variable mode imager</td>
			<td>Amersham Biosciences</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

efficient and site-specific antibody labeling by strain-promoted azide-alkyne cycloaddition

Derzeit gibt es viele chemische Werkzeuge zur Verfügung, chemische Sonden in Proteine ​​einzuführen ihrer Struktur und Funktion zu untersuchen. Ein geeignetes Verfahren ist Proteinkonjugation durch genetisch eine unnatürliche Aminosäure Einführen einer bioorthogonale funktionelle Gruppe enthalten. Dieser Bericht beschreibt ein detailliertes Protokoll für die ortsspezifische Antikörper-Konjugation. Das Protokoll umfasst die experimentelle Details für die genetische Einbau eines azidhaltigen Aminosäure und die Konjugationsreaktion durch dehnungs gefördert Azid-Alkin-Cyclo (SPAAC). Dieser Stamm-vermittelte Reaktion verläuft durch einfaches Mischen der reagierenden Moleküle bei physiologischem pH-Wert und Temperatur, und erfordert keine zusätzlichen Reagenzien wie Kupfer (I) -Ionen und Kupfer-Chelat-Liganden. Daher würde diese Methode für die allgemeine Proteinkonjugation und Entwicklung von Antikörper-Arzneimittel-Konjugate (ADCs) nützlich sein.

<html> In dieser Studie wurde ein Antikörperfragment ortsspezifisch mit einem Fluorophor konjugiert durch ein Azid enthaltenden Aminosäure in dem Fragment enthält , und das mutante Antikörperfragment mit einem gespannten Cyclooctin Umsetzung von (Abbildung 1). HerFab wurde als Zielantikörperfragment ausgewählt ist, in die AF als Azid-enthaltende Aminosäure eingebaut wurde. Zu dem Rückstand in HerFab für den Ersatz mit AF, die Röntgenkristallstruktur von HerFab w...

Watch this Scientific Journal Video about Efficient and Site-specific Antibody Labeling by Strain-promoted Azide-alkyne Cycloaddition at JoVE.com

Efficient and Site-specific Antibody Labeling by Strain-promoted Azide-alkyne Cycloaddition

Here, we present a protocol to site-specifically introduce chemical probes into an antibody fragment by genetically incorporating an azide-containing amino acid, and subsequently coupling the azide with a chemical probe by strain-promoted azide-alkyne cycloaddition (SPAAC).

Effiziente und ortsspezifische Antikörpermarkierung von Dehnungs gefördert Azid-Alkin-Cyclo

There are currently many chemical tools available to introduce chemical probes into proteins to study their structure and function. A useful method is ...

efficient-site-specific-antibody-labeling-strain-promoted-azide

Research

JoVE Journal

Biochemistry

20.5K Aufrufe.  Sogang University. Here, we present a protocol to site-specifically introduce chemical probes into an antibody fragment by genetically incorporating an azide-containing amino acid, and subsequently coupling the azide with a chemical probe by strain-promoted azide-alkyne cycloaddition (SPAAC).

Serie: Efficient and Site-specific Antibody Labeling by Strain-promoted Azide-alkyne Cycloaddition

Identification of Small Molecule-binding Proteins in a Native Cellular Environment by Live-cell Photoaffinity Labeling

Identifying the molecular target(s) of small molecules is a challenging but necessary step towards understanding their mechanism of action. While several target identification methods have been developed and used to successfully elucidate the binding proteins of a variety of small molecules, these techniques have drawbacks that make them unsuitable for detecting certain types of small molecule-target interactions. In particular, non-covalent interactions that depend on native cellular conditions, such as those of membrane proteins whose structures may be perturbed upon cell lysis, are often not amenable to affinity-based target identification methods. Here, we demonstrate a method wherein a probe containing a photolabile group is used to covalently crosslink to the small molecule binding protein within the environment of the live cell, allowing the detection and isolation of the target protein without the need for maintenance of the interaction after cell lysis. This technique is a valuable tool for studying biologically interesting small molecules with unknown mechanisms, both in the context of basic biology as well as drug discovery.

We describe here a method for identification of small molecule-binding proteins using photoaffinity labeling. The advantage of this technique is that binding and covalent labeling of the target proteins occurs within the live cellular environment, removing the risk of disrupting native protein structure and binding conditions upon cell lysis.

Identifizierung von kleinen Molekülen-bindende Proteine ​​in nativer zellulären Umgebung von lebenden Zellen Photoaffinitatsmarkierung

Identifying the molecular target(s) of small molecules is a challenging but necessary step towards understanding their mechanism of action. While several ...

Forschung

Biochemie

A Facile and Efficient Approach for the Production of Reversible Disulfide Cross-linked Micelles

Nanomedicine is an emerging form of therapy that harnesses the unique properties of particles that are nanometers in scale for biomedical application. Improving drug delivery to maximize therapeutic outcomes and to reduce drug-associated side effects are some of the cornerstones of present-day nanomedicine. Nanoparticles in particular have found a wide application in cancer treatment. Nanoparticles that offer a high degree of flexibility in design, application, and production based on the tumor microenvironment are projected to be more effective with rapid translation into clinical practice. The polymeric micellar nano-carrier is a popular choice for drug delivery applications.
In this article, we describe a simple and effective protocol for synthesizing drug-loaded, disulfide cross-linked micelles based on the self-assembly of a well-defined amphiphilic linear-dendritic copolymer (telodendrimer, TD). TD is composed of polyethylene glycol (PEG) as the hydrophilic segment and a thiolated cholic acid cluster as the core-forming hydrophobic moiety attached stepwise to an amine-terminated PEG using solution-based peptide chemistry. Chemotherapy drugs, such as paclitaxel (PTX), can be loaded using a standard solvent evaporation method. The O2-mediated oxidation was previously utilized to form intra-micellar disulfide cross-links from free thiol groups on the TDs. However, the reaction was slow and not feasible for large-scale production. Recently, an H2O2-mediated oxidation method was explored as a more feasible and efficient approach, and it was 96 times faster than the previously reported method. Using this approach, 50 g of PTX-loaded, disulfide cross-linked nanoparticles have been successfully produced with narrow particle size distribution and high drug loading efficiency. The stability of the resulting micelle solution is analyzed using disrupting conditions such as co-incubation with a detergent, sodium dodecyl sulfate, with or without a reducing agent. The drug-loaded, disulfide cross-linked micelles demonstrated less hemolytic activity when compared to their non-cross-linked counterparts.

To deliver cancer drugs to tumor sites with high specificity and reduced side effects, new methods based on nanoparticles are required. Here, we describe disulfide cross-linked micelles that can be easily prepared by hydrogen peroxide-mediated oxidation and are able to dissociate efficiently under a reducing tumor environment to release payloads.

Eine leichte und effiziente Ansatz für die Produktion von Reversible Disulfid Vernetzte Mizellen

Nanomedicine is an emerging form of therapy that harnesses the unique properties of particles that are nanometers in scale for biomedical application. ...

Laboratory Scale Production and Purification of a Therapeutic Antibody

Ensuring the successful production of a therapeutic antibody begins early on in the development process. The first stage is vector expression of the antibody genes followed by stable transfection into a suitable cell line. The stable clones are subjected to screening in order to select those clones with desired production and growth characteristics. This is a critical albeit time-consuming step in the process. This protocol considers vector selection and sourcing of antibody sequences for the expression of a therapeutic antibody. The methods describe preparation of vector DNA for stable transfection of a suspension variant of human embryonic kidney 293 (HEK-293) cell line, using polyethylenimine (PEI). The cells are transfected as adherent cells in serum-containing media to maximize transfection efficiency, and afterwards adapted to serum-free conditions. Large scale production, setup as batch overgrow cultures is used to yield antibody protein that is purified by affinity chromatography using an automated fast protein liquid chromatography (FPLC) instrument. The antibody yields produced by this method can provide sufficient protein to begin initial characterization of the antibody. This may include in vitro assay development or physicochemical characterization to aid in the time-consuming task of clonal screening for lead candidates. This method can be transferable to the development of an expression system for the production of biosimilar antibodies.

This protocol describes the production of a therapeutic antibody in a mammalian expression system. The methods described include preparation of vector DNA, stable transfection and serum-free adaptation of a human embryonic kidney 293 cell line, set up of large scale cultures and purification using affinity chromatography.

Labormaßstab Herstellung und Reinigung eines therapeutischen Antikörpers

Ensuring the successful production of a therapeutic antibody begins early on in the development process. The first stage is vector expression of the ...

Enhanced Sample Multiplexing of Tissues Using Combined Precursor Isotopic Labeling and Isobaric Tagging (cPILOT)

There is an increasing demand to analyze many biological samples for disease understanding and biomarker discovery. Quantitative proteomics strategies that allow simultaneous measurement of multiple samples have become widespread and greatly reduce experimental costs and times. Our laboratory developed a technique called combined precursor isotopic labeling and isobaric tagging (cPILOT), which enhances sample multiplexing of traditional isotopic labeling or isobaric tagging approaches. Global cPILOT can be applied to samples originating from cells, tissues, bodily fluids, or whole organisms and gives information on relative protein abundances across different sample conditions. cPILOT works by 1) using low pH buffer conditions to selectively dimethylate peptide N-termini and 2) using high pH buffer conditions to label primary amines of lysine residues with commercially-available isobaric reagents (see Table of Materials/Reagents). The degree of sample multiplexing available is dependent on the number of precursor labels used and the isobaric tagging reagent. Here, we present a 12-plex analysis using light and heavy dimethylation combined with six-plex isobaric reagents to analyze 12 samples from mouse tissues in a single analysis. Enhanced multiplexing is helpful for reducing experimental time and cost and more importantly, allowing comparison across many sample conditions (biological replicates, disease stage, drug treatments, genotypes, or longitudinal time-points) with less experimental bias and error. In this work, the global cPILOT approach is used to analyze brain, heart, and liver tissues across biological replicates from an Alzheimer&#39;s disease mouse model and wild-type controls. Global cPILOT can be applied to study other biological processes and adapted to increase sample multiplexing to greater than 20 samples.

Enhanced Sample Multiplexing of Tissues Using Combined Precursor Isotopic Labeling and Isobaric Tagging cPILOT

Combined precursor isotopic labeling and isobaric tagging (cPILOT) is a quantitative proteomics strategy that enhances sample multiplexing capabilities of isobaric tags. This protocol describes the application of cPILOT to tissues from an Alzheimer's disease mouse model and wild-type controls.

Verbesserte Sample Multiplexing von Gewebe mit Combined Precursor Isotopenmarkierung und Isobaric Tagging (cPILOT)

There is an increasing demand to analyze many biological samples for disease understanding and biomarker discovery. Quantitative proteomics strategies ...

Analysis of Histone Antibody Specificity with Peptide Microarrays

Post-translational modifications (PTMs) on histone proteins are widely studied for their roles in regulating chromatin structure and gene expression. The mass production and distribution of antibodies specific to histone PTMs has greatly facilitated research on these marks. As histone PTM antibodies are key reagents for many chromatin biochemistry applications, rigorous analysis of antibody specificity is necessary for accurate data interpretation and continued progress in the field. This protocol describes an integrated pipeline for the design, fabrication and use of peptide microarrays for profiling the specificity of histone antibodies. The design and analysis aspects of this procedure are facilitated by ArrayNinja, an open-source and interactive software package we recently developed to streamline the customization of microarray print formats. This pipeline has been used to screen a large number of commercially available and widely used histone PTM antibodies, and data generated from these experiments are freely available through an online and expanding Histone Antibody Specificity Database. Beyond histones, the general methodology described herein can be applied broadly to the analysis of PTM-specific antibodies.

This manuscript describes methods for applying peptide microarray technology to specificity profiling of antibodies that recognize histones and their post-translational modifications.

Analyse der Histon-Antikörper-Spezifität mit Peptid-Microarrays

Post-translational modifications (PTMs) on histone proteins are widely studied for their roles in regulating chromatin structure and gene expression. The ...

Deep Proteome Profiling by Isobaric Labeling, Extensive Liquid Chromatography, Mass Spectrometry, and Software-assisted Quantification

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) coupled to tandem mass spectrometry (LC-MS/MS) and isobaric labeling multiplexing capacity. Here, we introduce a deep-proteomics profiling protocol that combines 10-plex tandem mass tag (TMT) labeling with an extensive LC/LC-MS/MS platform, and post-MS computational interference correction to accurately quantitate whole proteomes. This protocol includes the following main steps: protein extraction and digestion, TMT labeling, 2-dimensional (2D) LC, high-resolution mass spectrometry, and computational data processing. Quality control steps are included for troubleshooting and evaluating experimental variation. More than 10,000 proteins in mammalian samples can be confidently quantitated with this protocol. This protocol can also be applied to the quantitation of post translational modifications with minor changes. This multiplexed, robust method provides a powerful tool for proteomic analysis in a variety of complex samples, including cell culture, animal tissues, and human clinical specimens.

We present a protocol to accurately quantitate proteins with isobaric labelling, extensive fractionation, bioinformatics tools, and quality control steps in combination with liquid chromatography interfaced to a high-resolution mass spectrometer.

Tiefen Proteom Profilierung durch isobare Kennzeichnung, umfangreiche Flüssigchromatographie-Massenspektrometrie und softwaregestützte Quantifizierung

Many exceptional advances have been made in mass spectrometry (MS)-based proteomics, with particular technical progress in liquid chromatography (LC) ...

Method for Efficient Refolding and Purification of Chemoreceptor Ligand Binding Domain

Identification of natural ligands of chemoreceptors and structural studies aimed at elucidation of the molecular basis of the ligand specificity can be greatly facilitated by the production of milligram amounts of pure, folded ligand binding domains. Attempts to heterologously express periplasmic ligand binding domains of bacterial chemoreceptors in Escherichia coli (E. coli) often result in their targeting into inclusion bodies. Here, a method is presented for protein recovery from inclusion bodies, its refolding and purification, using the periplasmic dCACHE ligand binding domain of Campylobacter jejuni (C. jejuni) chemoreceptor Tlp3 as an example. The approach involves expression of the protein of interest with a cleavable His6-tag, isolation and urea-mediated solubilisation of inclusion bodies, protein refolding by urea depletion, and purification by means of affinity chromatography, followed by tag removal and size-exclusion chromatography. The circular dichroism spectroscopy is used to confirm the folded state of the pure protein. It has been demonstrated that this protocol is generally useful for production of milligram amounts of dCACHE periplasmic ligand binding domains of other bacterial chemoreceptors in a soluble and crystallisable form.

A procedure is presented for the refolding of the dCACHE periplasmic ligand binding domain of Campylobacter jejuni chemoreceptor Tlp3 from inclusion bodies and the purification to yield milligram quantities of protein.

Methode für effiziente Umfaltung und Reinigung des Chemorezeptor-Liganden-bindende Domäne

Identification of natural ligands of chemoreceptors and structural studies aimed at elucidation of the molecular basis of the ligand specificity can be ...

Isolation of Glomeruli and In Vivo Labeling of Glomerular Cell Surface Proteins

Proteinuria results from the disruption of the glomerular filter that is composed of the fenestrated endothelium, glomerular basement membrane, and podocytes with their slit diaphragms. The delicate structure of the glomerular filter, especially the slit diaphragm, relies on the interplay of diverse cell surface proteins. Studying these cell surface proteins has so far been limited to in vitro studies or histologic analysis. Here, we present a murine in vivo biotinylation labeling method, which enables the study of glomerular cell surface proteins under physiologic and pathophysiologic conditions. This protocol contains information on how to perfuse mouse kidneys, isolate glomeruli, and perform endogenous immunoprecipitation of a protein of interest. Semi-quantitation of glomerular cell surface abundance is readily available with this novel method, and all proteins accessible to biotin perfusion and immunoprecipitation can be studied. In addition, isolation of glomeruli with or without biotinylation enables further analysis of glomerular RNA and protein as well as primary glomerular cell culture (i.e., primary podocyte cell culture).

Isolation of Glomeruli and In Vivo Labeling of Glomerular Cell Surface Proteins

Here we present a protocol for murine in vivo labeling of glomerular cell surface proteins with biotin. This protocol contains information on how to perfuse mouse kidneys, isolate glomeruli, and perform endogenous immunoprecipitation of the protein of interest.

Isolierung der Glomeruli und In Vivo Kennzeichnung der glomerulären Zelle Oberflächenproteine

Proteinuria results from the disruption of the glomerular filter that is composed of the fenestrated endothelium, glomerular basement membrane, and ...

Proteome-wide Quantification of Labeling Homogeneity at the Single Molecule Level

Cell proteomes are often characterized using electrophoresis assays, where all species of proteins in the cells are non-specifically labeled with a fluorescent dye and are spotted by a photodetector following their separation. Single molecule fluorescence imaging can provide ultrasensitive protein detection with its ability for visualizing individual fluorescent molecules. However, the application of this powerful imaging method to electrophoresis assays is hampered by the lack of ways to characterize the homogeneity of fluorescent labeling of each protein species across the proteome. Here, we developed a method to evaluate the labeling homogeneity across the proteome based on a single molecule fluorescence imaging assay. In our measurement using a HeLa cell sample, the proportion of proteins labeled with at least one dye, which we termed &#8216;labeling occupancy&#8217; (LO), was determined to range from 50% to 90%, supporting the high potential of the application of single molecule imaging to sensitive and precise proteome analysis.

Here, we present a protocol to assess the labeling homogeneity for each protein species in a complex protein sample at the single molecule level.

Proteom-weite Quantifizierung des Benennens Homogenität auf der Ebene des einzelnen Moleküls

Cell proteomes are often characterized using electrophoresis assays, where all species of proteins in the cells are non-specifically labeled with a ...

Creating Highly Specific Chemically Induced Protein Dimerization Systems by Stepwise Phage Selection of a Combinatorial Single-Domain Antibody Library

Protein dimerization events that occur only in the presence of a small-molecule ligand enable the development of small-molecule biosensors for the dissection and manipulation of biological pathways. Currently, only a limited number of chemically induced dimerization (CID) systems exist and engineering new ones with desired sensitivity and selectivity for specific small-molecule ligands remains a challenge in the field of protein engineering. We here describe a high throughput screening method, combinatorial binders-enabled selection of CID (COMBINES-CID), for the de novo engineering of CID systems applicable to a large variety of ligands. This method uses the two-step selection of a phage-displayed combinatorial nanobody library to obtain 1) &#34;anchor binders&#34; that first bind to a ligand of interest and then 2) &#34;dimerization binders&#34; that only bind to anchor binder-ligand complexes. To select anchor binders, a combinatorial library of over 109 complementarity-determining region (CDR)-randomized nanobodies is screened with a biotinylated ligand and hits are validated with the unlabeled ligand by bio-layer interferometry (BLI). To obtain dimerization binders, the nanobody library is screened with anchor binder-ligand complexes as targets for positive screening and the unbound anchor binders for negative screening. COMBINES-CID is broadly applicable to select CID binders with other immunoglobulin, non-immunoglobulin, or computationally designed scaffolds to create biosensors for in vitro and in vivo detection of drugs, metabolites, signaling molecules, etc.

Creating chemically induced protein dimerization systems with desired affinity and specificity for any given small molecule ligand would have many biological sensing and actuation applications. Here, we describe an efficient, generalizable method for de novo engineering of chemically induced dimerization systems via the stepwise selection of a phage-displayed combinatorial single-domain antibody library.

Erstellen hochspezifischer chemisch induzierter Proteindimerisierungssysteme durch schrittweise Phage-Auswahl einer kombinatorischen Single-Domain-Antikörperbibliothek