Este trabalho foi financiado pelo National Institutes of Health concessão GM086822 e National Science Foundation grande pesquisa instrumentação concessão DBI-0960313. Os autores gostariam de agradecer as Dras. Jon Miyake &amp; Donna Hardy (Bio-Rad) e Jennifer Loertscher (Seattle University), pela sua competência técnica. Seleccionar reagentes de cromatografia e instrumentação suplementar foram generosamente fornecidas pelo Bio-Rad.

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	<li>Cummins, P. M., O'Connor, B. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophobic+interaction+chromatography.">Hydrophobic interaction chromatography.</a> Methods Mol. Biol. 681, 431-437 (2011).</li><li>Nagrath, D., Xia, F., Cramer, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+and+modeling+of+nonlinear+hydrophobic+interaction+chromatographic+systems.">Characterization and modeling of nonlinear hydrophobic interaction chromatographic systems.</a> J. Chromatogr. A. 1218, 1219-1226 (2011).</li><li>To, B. C., Lenhoff, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophobic+interaction+chromatography+of+proteins.+IV.+Protein+adsorption+capacity+and+transport+in+preparative+mode.">Hydrophobic interaction chromatography of proteins. IV. Protein adsorption capacity and transport in preparative mode.</a> J. Chromatogr. A. 1218, 427-440 (2011).</li><li>Huddleston, J. 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C., Banh, C., Brossay, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=L.A+Protocol+for+the+Production+of+KLRG1+Tetramer.">L.A Protocol for the Production of KLRG1 Tetramer.</a> J. Vis. Exp. (35), e1701-e1701 (2010).</li><li>Murphy, P. J. M., Morishima, Y., Kovacs, J. J., Yao, T. P., Pratt, W. B. <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+dynamics+of+hsp90+action+on+the+glucocorticoid+receptor+by+acetylation/deacetylation+of+the+chaperone.">Regulation of the dynamics of hsp90 action on the glucocorticoid receptor by acetylation/deacetylation of the chaperone.</a> J. Biol. Chem. 280, 33792-33799 (2005).</li><li>Zeytuni, N., Zarivach, 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+of+the+M.+magneticum+strain+AMB-1+Magnetosome+Associated+Protein+MamA&#916;41.">Purification of the M. magneticum strain AMB-1 Magnetosome Associated Protein MamA&#916;41.</a> J. Vis. Exp. (37), 10-3791 (2010).</li><li>Kong, Y., Li, X., Bai, G., Ma, G., Su, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+automatic+system+for+multidimensional+integrated+protein+chromatography.">An automatic system for multidimensional integrated protein chromatography.</a> J. Chromatogr. A. 1217, 6898-6904 (2010).</li><li>Camper, D. V., Viola, 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=Fully+automated+protein+purification.">Fully automated protein purification.</a> Anal. Biochem. 393, 176-181 (2009).</li><li>Hammon, J., Palanivelu, D. V., Chen, J., Patel, C., Minor, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+green+fluorescent+protein+screen+for+identification+of+well-expressed+membrane+proteins+from+a+cohort+of+extremophilic+organisms.">A green fluorescent protein screen for identification of well-expressed membrane proteins from a cohort of extremophilic organisms.</a> Protein Sci. 18, 121-133 (2009).</li><li>Wu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+green+and+red+fluorescent+proteins+to+teach+protein+expression,+purification,+and+crystallization.">Using green and red fluorescent proteins to teach protein expression, purification, and crystallization.</a> Biochem. Mol. Biol. Educ. 36, 43-54 (2008).</li><li>Queiroz, J. A., Tomaz, C. T., Cabral, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrophobic+interaction+chromatography+of+proteins.">Hydrophobic interaction chromatography of proteins.</a> J. Biotechnol. 87, 143-159 (2001).</li><li>McCue, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Theory+and+use+of+hydrophobic+interaction+chromatography+in+protein+purification+applications.">Theory and use of hydrophobic interaction chromatography in protein purification applications.</a> Methods Enzymol. 463, 405-414 (2009).</li></ol>

Seleccionar reagentes de cromatografia e instrumentação suplementar foram fornecidos pela Bio-Rad.

Técnicas de cromatografia líquida provaram inestimável para a preparação de proteínas altamente purificadas necessárias para a realização de 6 imunológica, bioquímica 7, e 8 estudos estruturais. Métodos de purificação HIC mais frequentemente requer a determinação empírica de um meio preferido, e estrutura de ligando, a densidade de ligando, e as propriedades da matriz do grânulo todos têm sido mostrados para impacto nos resultados cromatográficas 2, 3. Coluna automatizado de aferição é uma abordagem eficiente para a seleção de um meio de HIC para otimização subseqüente e purificação de proteínas 4. O método automatizado coluna de aferição apresentados podem ser prontamente adaptado para várias estratégias de purificação de proteínas HIC. Alterações na concentração de sal, a escolha do sal, gradiente de sal, e pH pode melhorar ainda mais as condições de purificação, e os efeitos da variação destes parâmetros essenciais foram previamente analisado 13,14. Eluato de HIC contendo uma prote alvo parcialmente purificadain pode ser adicionalmente purificado utilizando uma técnica cromatográfica complementar, tal como cromatografia de permuta iónica (IEX) ou de exclusão em gel de filtração / tamanho cromatografia 9,10. Devido à sua absorvância de luz original e características de emissão, o perfil de eluição de GFP podem ser identificados utilizando, em linha e pós-run abordagens. Para esse efeito, este protocolo pode ainda ser adaptada para a purificação de recombinantes GFP de fusão de proteínas, em que uma proteína-alvo não relacionado é &quot;marcado&quot; com GFP. Proteínas alvo GFP pode ser detectada com luz UV 11 e purificado utilizando várias abordagens cromatográficas, incluindo a estratégia de purificação HIC descrito acima. Purificação GFP também se tornou um marco pedagógico nos laboratórios de bioquímica para o ensino de técnicas de proteína ciência moderna 12. Enquanto a purificação da proteína básica de HIC pode ser conduzida usando uma substancialmente menos robusto cromatografia syhaste, a instrumentação aqui apresentado tem um número de vantagens distintas para auxiliar na obtenção de resultados favoráveis. Benefícios notáveis ​​de se utilizar um sistema altamente automatizado incluem a melhoria executar-a-correr condição de reprodutibilidade, tempo de poupança, e diminuiu oportunidades para o ar a ser introduzidos no sistema 10. Sistema controlado mistura de tampão, o que é facilitado pela maximizer sistema, permite a consistência aumentou na preparação de tampão e reprodutibilidade experimental. Desenho carga de amostra suficiente para a ansa de amostragem dinâmico para todos aferição é executado assegura ainda mais a uniformidade da amostra a ser adicionado a cada coluna e permite que para execuções sequenciais sem interrupção ou manual de recarga. Injecção da amostra controlado a partir do circuito de amostra na coluna diminui variabilidade que pode ocorrer com carregamento manual da amostra. Um par de válvulas de selecção de coluna permitir para execuções de amostra consecutivos, cada um utilizando uma coluna HIC diferente, sem ter de replumb o sistema. Executando mul<html> ti-comprimento de onda de análise é particularmente benéfico quando se examina uma proteína com um perfil único espectrofotométrico. Além disso a GFP, citocromos, flavoproteínas, e outros heme contendo proteínas podem beneficiar deste técnica. Dispositivos de monitorização de condutividade e pH permitir a verificação de tempo real condições experimentais. Dividir recolha eluato fracção permite a manipulação fracção melhorada e permite a transferência fácil para os métodos de pós-executar a análise que requerem um mínimo volume de amostra (por exemplo, ELISA, SDS-PAGE, Western blot, e Experion electroforese microfluídico). Ao operar off-line segundo coletor fração requer sincronização manual, que permite a máxima flexibilidade na seleção de coletores de fração. As desvantagens mais significativas para a utilização como um sistema de cromatografia robusto para a coluna HIC aferição e purificação de proteínas incluem o tempo inicial e as despesas orçamentais associados à aquisição de instrumentos e treinamento do operador. t &quot;&gt; O protocolo apresentado aqui utiliza um Bio-Rad DuoFlow sistema de cromatografia;. no entanto, a instrumentação igualmente robusta de outros fabricantes, tais como o Avant Akta da GE Healthcare, podem também ser utilizados e são capazes de produzir resultados equivalentes sistema de cromatografia Mesmo comparável têm características únicas de programação (por exemplo, limitações, método de nomenclatura de componentes, a preferência do operador, e escalabilidade) que devem ser considerados antes de iniciar um processo de purificação ou aquisição de instrumentos.

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td><td> Comentários (opcional) </td></tr><tr><td> <a href="http://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=223301" target="_blank">BioLogic DuoFlow Pathfinder 20 Sistema</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="http://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=223301" target="_blank">7602257</a> </td><td> Inclui sistema maximizador, mixer, estação de trabalho F10, AVR7-3 da válvula, QuadTec UV / Vis detector com célula de fluxo, coletor de fração BioFrac, software BioLogic, e kit de iniciação </td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=760-0408&vertical=LSR&parentCategoryGUID=22c495f1-36ff-44a3-9140-ee7e54d0b1ba" target="_blank">AVR9-8-stream selecionar válvula</a><html></td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=760-0408&vertical=LSR&parentCategoryGUID=22c495f1-36ff-44a3-9140-ee7e54d0b1ba" target="_blank">7600408</a> </td><td> De alta pressão da válvula, 9-porta, posição 8, 3.500 psi (233 bar) limite, para uso com o sistema DuoFlow BioLogic </td></tr><tr><td> Desviador válvula SV3T-2 </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> 7600410 </td><td> Válvula de solenóide, 3-porta, posição 2, 30 psi (2 bar) limite, para uso com o sistema DuoFlow BioLogic </td></tr><tr><td> Stream Splitter válvula </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td></td><td></td></tr><tr><td>tical = LSR &amp; parentCategoryGUID = 22c495f1-36ff-44a3-9140-ee7e54d0b1ba &quot;target =&quot; _blank &quot;&gt; DynaLoop 25 Kit </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=750-0451&vertical=LSR&parentCategoryGUID=22c495f1-36ff-44a3-9140-ee7e54d0b1ba" target="_blank">7500451</a> </td><td> Sliding pistão kit de amostragem, inclui 25 ml de deslizamento DynaLoop laço pistão, DynaLoop partes kit (# 750-0450) </td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/LSR/PDP/ec82e7b4-919e-428b-ac03-9adf1f50a48e/BioFractrade_Fraction_Collector" target="_blank">Coletor de Frações BioFrac</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/LSR/PDP/ec82e7b4-919e-428b-ac03-9adf1f50a48e/BioFractrade_Fraction_Collector" target="_blank">7410002</a> </td><td> Dois col fração<html> leitores utilizado </td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=741-0088&vertical=LSR&parentCategoryGUID=ec82e7b4-919e-428b-ac03-9adf1f50a48e" target="_blank">BioFrac microplaca adaptador cabeça queda</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=741-0088&vertical=LSR&parentCategoryGUID=ec82e7b4-919e-428b-ac03-9adf1f50a48e" target="_blank">7410088</a> </td><td></td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&vertical=LSR&country=US&lang=en&productID=741-0017" target="_blank">BioFrac adaptador placa de microtitulação</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td>&amp; Country = EUA &amp; lang = pt &amp; ProductID = 741-0017 &quot;target =&quot; _blank &quot;&gt; 7410017 </td><td></td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=750-0202&vertical=LSR&parentCategoryGUID=c140016b-1958-4a91-be4c-8645a4c8204f" target="_blank">Optics UV Módulo</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=750-0202&vertical=LSR&parentCategoryGUID=c140016b-1958-4a91-be4c-8645a4c8204f" target="_blank">7500202</a> </td><td></td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=catProductDetail&isFromSearch=true&productID=760-1331&vertical=LSR&parentCategoryGUID=c4095dc1-9260-4431-b066-823b050048c8" target="_blank">Lâmpada halógena</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> &lt;<html> um target = &quot;_blank&quot;&gt; 7601331 </td><td></td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=220901" target="_blank">Econo Bomba Gradiente</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=220901" target="_blank">7319001</a> </td><td> bomba de gradiente de baixa pressão purificação de proteínas, inclui tubagem e kit de acessórios </td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=224301" target="_blank">Experion Sistema</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td>bio-rad.com/prd/en/US/adirect/biorad? cmd = BRCatgProductDetail &amp; ProductID = 224301 &quot;target =&quot; _blank &quot;&gt; 7007001 </td><td></td></tr><tr><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=224101" target="_blank">Experion Kit Análise Pro260</a> </td><td> <a href="http://www.bio-rad.com/" target="_blank">Bio-Rad</a> </td><td> <a href="https://www.bio-rad.com/prd/en/US/adirect/biorad?cmd=BRCatgProductDetail&productID=224101" target="_blank">7007102</a> </td><td></td></tr><tr><td> HiTrap kit seleção HIC coluna </td><td> GE Healthcare </td><td> 28-4110-07 </td><td> Inclui 7 x 1 ml pré-embalados colunas de mídia HIC para aferição </td></tr><tr><td> GE Healthcare para a Bio-Rad acessórios coluna </td><td> GE Healthcare </td><td> 18111251 e 18111257 </td><td></td></tr></tbody></table>

automated hydrophobic interaction chromatography column selection for use in protein purification

Em contraste com outros métodos cromatográficos para proteínas de purificação (por exemplo, filtração em gel, afinidade e de troca iónica), cromatografia de interacção hidrofóbica (HIC) comumente requer determinação experimental (referido como triagem ou &quot;scouting&quot;), a fim de seleccionar o meio mais adequado para cromatografia para a purificação de uma dada proteína 1. O método aqui apresentado descreve uma abordagem automatizada para aferição para um meio óptimas HIC a serem utilizados na purificação de proteínas. HIC separa proteínas e outras biomoléculas a partir de um lisado bruto com base nas diferenças de hidrofobicidade. Semelhante a cromatografia de afinidade (AC) e cromatografia de permuta iónica (IEX), HIC é capaz de se concentrar a proteína de interesse à medida que progride através do processo cromatográfico. Proteínas mais adequados para a purificação por HIC incluem aqueles com regiões superfície hidrofóbica e capaz de suportar a exposição a concentrações de sal em excesso de 2 ammo Mtitânio sulfato de ((NH4) 2 SO 4). HIC é muitas vezes escolhido como um método de purificação para proteínas que faltam um marcador de afinidade e, portanto, inadequado para AC, e quando IEX não fornecer purificação adequada. Porções hidrofóbicas na superfície da proteína temporariamente se ligar a um ligando não polar acoplado a uma matriz inerte, imóvel. A interacção entre a proteína e do ligando são altamente dependente da concentração de sal do tampão que flui através da coluna de cromatografia, com altas concentrações iónicas reforçar a interacção proteína-ligando e tornando a proteína imóvel (isto é, ligado no interior da coluna) 2. Como diminuir as concentrações de sal, a interacção proteína-ligando dissipa, a proteína torna-se novamente móvel e elui da coluna. Vários meios HIC estão disponíveis comercialmente em pré-embalados colunas, cada uma contendo de vários ligandos hidrofóbicos (por exemplo, S-butilo, butilo, octilo, e fenil) reticulado em diferentes densidades de esferas de agarose de uma especificaçãodiâmetro ific 3. Coluna Automated aferição permite uma abordagem eficiente para determinar que a mídia HIC deve ser empregada para o futuro, experimentos de otimização mais exaustivos e purificação de proteínas é executado 4. A proteína específica a ser purificado é aqui recombinante da proteína verde fluorescente (GFP), no entanto, a abordagem pode ser adaptado para a purificação de outras proteínas com uma ou mais regiões superfície hidrofóbica. GFP serve como um modelo útil proteína, devido à sua estabilidade, único pico de absorvância de luz a 397 nm, e de fluorescência quando exposta à luz UV 5. Lisado bacteriano contendo GFP do tipo selvagem foi preparado de um tampão de elevado teor de sal, carregado num meio DuoFlow Bio-Rad a pressão do sistema de cromatografia líquida, e adsorvido a colunas HiTrap HIC contendo diferentes meios HIC. A proteína foi eluída das colunas e analisadas por in-line e métodos de pós-run de detecção. Mistura de buffer, a injeção de ciclo dinâmico amostra, col seqüencialUMN selecção, multi-comprimento de onda, análise e de divisão de recolha eluato fracção aumentou a funcionalidade do sistema ea reprodutibilidade da abordagem experimental.

Watch this Scientific Journal Video about Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification at JoVE.com

Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification

Um método automático para a identificação de interacção hidrofóbica adequados cromatografia (HIC) meios de comunicação para ser utilizados no processo de purificação de proteínas é apresentada. O método utiliza um meio de pressão-sistema de cromatografia líquida incluindo mistura de tampão automatizado, injecção lacete dinâmica amostra, a selecção de coluna sequencial, multi-comprimento de onda de análise, e recolha de divisão eluato fracção.

Automated interação hidrofóbica Seleção coluna de cromatografia para uso na purificação de proteínas

In contrast to other chromatographic methods for purifying proteins (e.g. gel filtration, affinity, and ion exchange), hydrophobic interaction ...

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Biology

43.2K visualizações.  Seattle University. Um método automático para a identificação de interacção hidrofóbica adequados cromatografia (HIC) meios de comunicação para ser utilizados no processo de purificação de proteínas é apresentada. O método utiliza um meio de pressão-sistema de cromatografia líquida incluindo mistura de tampão automatizado, injecção lacete dinâmica amostra, a selecção de coluna sequencial, multi-comprimento de onda de análise, e recolha de divisão eluato fracção.

Vídeo: Automated Hydrophobic Interaction Chromatography Column Selection for Use in Protein Purification

Staining of Proteins in Gels with Coomassie G-250 without Organic Solvent and Acetic Acid

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents (Methanol, Ethanol or 2-Propanol) and acetic acid are used for fixation, staining and destaining of proteins in a gel after SDS-PAGE. To speed up the procedure, heating the staining solution in the microwave oven for a short time is frequently used. This usually results in evaporation of toxic or hazardous Methanol, Ethanol or 2-Propanol and a strong smell of acetic acid in the lab which should be avoided due to safety considerations. In a protocol originally published in two patent applications by E.M. Wondrak (US2001046709 (A1), US6319720 (B1)), an alternative composition of the staining solution is described in which no organic solvent or acid is used. The CBB is dissolved in bidistilled water (60-80mg of CBB G-250 per liter) and 35 mM HCl is added as the only other compound in the staining solution. The CBB staning of the gel is done after SDS-PAGE and thorough washing of the gel in bidistilled water. By heating the gel during the washing and staining steps, the process can be finished faster and no toxic or hazardous compunds are evaporating. The staining of proteins occurs already within 1 minute after heating the gel in staining solution and is fully developed after 15-30 min with a slightly blue background that is destained completely by prolonged washing of the stained gel in bidistilled water, without affecting the stained protein bands.

A short protocol for protein staining with Coomassie Brilliant Blue (CBB) G-250 in polyacrylamide gels is described without using organic solvents or acetic acid as in the classical staining procedures with CBB.

Coloração de proteínas em géis com Coomassie G-250 sem ácido acético e Solventes Orgânicos

In classical protein staining protocols using Coomassie Brilliant Blue (CBB), solutions with high contents of toxic and flammable organic solvents ...

Biologia

Purification of the M. magneticum Strain AMB-1 Magnetosome Associated Protein MamA&Delta;41

Magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. This behavior is believed to aid their search for suitable environments (1). This capability is conferred by the magnetosome, a subcellular organelle that consists of a linear-chain assembly of lipid vesicles each able to biomineralize and enclose a ~50-nm crystal of magnetite or greigite. A principle component of the magnetosome that was shown to be required for the formation of functional vesicles is MamA. MamA is a highly abundant magnetosome-associated protein which is one of the most characterized magnetosome-associated proteins in vivo (2-6). This article focuses on the purification of MamA, which despite being studied in vivo, no clear functional or structural details have been identified for it. Bioinformatics analysis suggested that MamA is a tetra-tricopeptide repeat (TPR) containing protein. TPR is a structural motif found as such or forming part of a bigger fold in a wide range of proteins, it serves as a template for protein-protein interactions and mediates multi-protein complexes (7). TPRs are involved in many crucial tasks in eukaryotic cell organelle processes and many bacterial pathways (8-14). In order to understand MamA, a unique TPR containing protein, highly purified protein is required as a first step. In this article, we present the purification protocol for a stable MamA deletion mutant (MamA&Delta;41) from M. magneticum AMB-1.

Purification of the &lt;em&gt;M. magneticum&lt;/em&gt; Strain AMB-1 Magnetosome Associated Protein MamA&amp;Delta;41

MamA is a unique Magnetosome associated protein which was shown to be involved in magnetosome activation. Here we present the purification protocol of MamA deletion mutant (MamA&Delta;41) from M. magneticum AMB-1.

Purificação do M. magneticum Strain AMB-1 proteína associada Magnetosome MamAΔ41

Magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. This behavior is ...

Bimolecular Fluorescence Complementation (BiFC) Assay for Protein-Protein Interaction in Onion Cells Using the Helios Gene Gun

Investigation of gene function in diverse organisms relies on knowledge of how the gene products interact with each other in their normal cellular environment. The Bimolecular Fluorescence Complementation (BiFC) Assay1 allows researchers to visualize protein-protein interactions in living cells and has become an essential research tool. This assay is based on the facilitated association of two fragments of a fluorescent protein (GFP) that are each fused to a potential interacting protein partner. The interaction of the two protein partners would facilitate the association of the N-terminal and C-terminal fragment of GFP, leading to fluorescence. For plant researchers, onion epidermal cells are an ideal experimental system for conducting the BiFC assay because of the ease in obtaining and preparing onion tissues and the direct visualization of fluorescence with minimal background fluorescence. The Helios Gene Gun (BioRad) is commonly used for bombarding plasmid DNA into onion cells. We demonstrate the use of Helios Gene Gun to introduce plasmid constructs for two interacting Arabidopsis thaliana transcription factors, SEUSS (SEU) and LEUNIG HOMOLOG (LUH)2 and the visualization of their interactions mediated by BiFC in onion epidermal cells.

Bimolecular Fluorescence Complementation BiFC Assay for Protein-Protein Interaction in Onion Cells Using the Helios Gene Gun

This article illustrates how to properly use the BioRad Helios Gene Gun to introduce plasmid DNA into onion epidermal cells and how to test for protein-protein interactions in onion cells based on the principle of Bimolecular Fluorescence Complementation (BiFC)

Bimolecular de fluorescência de Complementação Assay (BiFC) para Interação Proteína-Proteína em células de cebola Utilizando o Gene Gun Helios

Investigation of gene function in diverse organisms relies on knowledge of how the gene products interact with each other in their normal cellular ...

Lipid Vesicle-mediated Affinity Chromatography using Magnetic Activated Cell Sorting (LIMACS): a Novel Method to Analyze Protein-lipid Interaction

The analysis of lipid protein interaction is difficult because lipids are embedded in cell membranes and therefore, inaccessible to most purification procedures. As an alternative, lipids can be coated on flat surfaces as used for lipid ELISA and Plasmon resonance spectroscopy. However, surface coating lipids do not form microdomain structures, which may be important for the lipid binding properties. Further, these methods do not allow for the purification of larger amounts of proteins binding to their target lipids.
 To overcome these limitations of testing lipid protein interaction and to purify lipid binding proteins we developed a novel method termed lipid vesicle-mediated affinity chromatography using magnetic-activated cell sorting (LIMACS). In this method, lipid vesicles are prepared with the target lipid and phosphatidylserine as the anchor lipid for Annexin V MACS. Phosphatidylserine is a ubiquitous cell membrane phospholipid that shows high affinity to the protein Annexin V. Using magnetic beads conjugated to Annexin V the phosphatidylserine-containing lipid vesicles will bind to the magnetic beads. When the lipid vesicles are incubated with a cell lysate the protein binding to the target lipid will also be bound to the beads and can be co-purified using MACS. This method can also be used to test if recombinant proteins reconstitute a protein complex binding to the target lipid. 
 We have used this method to show the interaction of atypical PKC (aPKC) with the sphingolipid ceramide and to co-purify prostate apoptosis response 4 (PAR-4), a protein binding to ceramide-associated aPKC. We have also used this method for the reconstitution of a ceramide-associated complex of recombinant aPKC with the cell polarity-related proteins Par6 and Cdc42. Since lipid vesicles can be prepared with a variety of sphingo- or phospholipids, LIMACS offers a versatile test for lipid-protein interaction in a lipid environment that resembles closely that of the cell membrane. Additional lipid protein complexes can be identified using proteomics analysis of lipid binding protein co-purified with the lipid vesicles.

Lipid Vesicle-mediated Affinity Chromatography using Magnetic Activated Cell Sorting LIMACS: a Novel Method to Analyze Protein-lipid Interaction

To test the interaction of a protein with its target lipid we used MACS and Annexin V-conjugated magnetic beads and lipid vesicles synthesized from the target lipid and Annexin V-binding phosphatidylserine. Proteins bound to the target lipid are co-purified and analyzed after elution from the beads.

Cromatografia de afinidade lipídica mediada por vesículas com separação de células Magnetic Ativado (LIMACS): um novo método para analisar proteínas lipídios Interação

The analysis of lipid protein interaction is difficult because lipids are embedded in cell membranes and therefore, inaccessible to most purification ...

Purification of Hsp104, a Protein Disaggregase

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key selective advantages. First, renaturation of disordered aggregates by Hsp104 empowers yeast survival after various protein-misfolding stresses, including heat shock3,5,11,12. Second, remodeling of cross-beta amyloid fibrils by Hsp104 enables yeast to exploit myriad prions (infectious amyloids) as a reservoir of beneficial and heritable phenotypic variation13-22. Remarkably, Hsp104 directly remodels preamyloid oligomers and amyloid fibrils, including those comprised of the yeast prion proteins Sup35 and Ure223-30. This amyloid-remodeling functionality is a specialized facet of yeast Hsp104. The E. coli orthologue, ClpB, fails to remodel preamyloid oligomers or amyloid fibrils26,31,32.
Hsp104 orthologues are found in all kingdoms of life except, perplexingly, animals. Indeed, whether animal cells possess any enzymatic system that couples protein disaggregation to renaturation (rather than degradation) remains unknown33-35. Thus, we and others have proposed that Hsp104 might be developed as a therapeutic agent for various neurodegenerative diseases connected with the misfolding of specific proteins into toxic preamyloid oligomers and amyloid fibrils4,7,23,36-38. There are no treatments that directly target the aggregated species associated with these diseases. Yet, Hsp104 dissolves toxic oligomers and amyloid fibrils composed of alpha-synuclein, which are connected with Parkinson's Disease23 as well as amyloid forms of PrP39. Importantly, Hsp104 reduces protein aggregation and ameliorates neurodegeneration in rodent models of Parkinson's Disease23 and Huntington's disease38. Ideally, to optimize therapy and minimize side effects, Hsp104 would be engineered and potentiated to selectively remodel specific aggregates central to the disease in question4,7. However, the limited structural and mechanistic understanding of how Hsp104 disaggregates such a diverse repertoire of aggregated structures and unrelated proteins frustrates these endeavors30,40-42.
To understand the structure and mechanism of Hsp104, it is essential to study the pure protein and reconstitute its disaggregase activity with minimal components. Hsp104 is a 102kDa protein with a pI of ~5.3, which hexamerizes in the presence of ADP or ATP, or at high protein concentrations in the absence of nucleotide43-46. Here, we describe an optimized protocol for the purification of highly active, stable Hsp104 from E. coli. The use of E. coli allows simplified large-scale production and our method can be performed quickly and reliably for numerous Hsp104 variants. Our protocol increases Hsp104 purity and simplifies His6-tag removal compared to a previous purification method from E. coli47. Moreover, our protocol is more facile and convenient than two more recent protocols26,48.

Here, we describe a protocol for the purification of highly active Hsp104, a hexameric AAA+ protein from yeast, which couples ATP hydrolysis to protein disaggregation. This scheme exploits a His6-tagged construct for affinity purification from E. coli followed by anion-exchange chromatography, His6-tag removal with TEV protease, and size-exclusion chromatography.

Purificação da Hsp104, um Disaggregase Protein

Hsp104 is a hexameric AAA+ protein1 from yeast, which couples ATP hydrolysis to protein disaggregation2-10 (Fig. 1). This activity imparts two key ...

A Protocol for Phage Display and Affinity Selection Using Recombinant Protein Baits

Using recombinant phage as a scaffold to present various protein portions encoded by a directionally cloned cDNA library to immobilized bait molecules is an efficient means to discover interactions. The technique has largely been used to discover protein-protein interactions but the bait molecule to be challenged need not be restricted to proteins. The protocol presented here has been optimized to allow a modest number of baits to be screened in replicates to maximize the identification of independent clones presenting the same protein. This permits greater confidence that interacting proteins identified are legitimate interactors of the bait molecule. Monitoring the phage titer after each affinity selection round provides information on how the affinity selection is progressing as well as on the efficacy of negative controls. One means of titering the phage, and how and what to prepare in advance to allow this process to progress as efficiently as possible, is presented. Attributes of amplicons retrieved following isolation of independent plaque are highlighted that can be used to ascertain how well the affinity selection has progressed. Trouble shooting techniques to minimize false positives or to bypass persistently recovered phage are explained. Means of reducing viral contamination flare up are discussed.

Phage display is a powerful technique to capture proteins or protein moieties that interact with an immobilized molecule of interest. Once a decision of the type of phage cDNA library to create and screen has been made, the protocol described here permits efficient affinity selection leading to identification of interactors.

Um protocolo para exibição Fago e Affinity Seleção Usando Iscas proteína recombinante

Using  recombinant phage as a scaffold to present various protein portions encoded by  a directionally cloned cDNA library to immobilized bait molecules ...

Identifying Protein-protein Interaction in Drosophila Adult Heads by Tandem Affinity Purification (TAP)

Genetic screens conducted using Drosophila melanogaster (fruit fly) have made numerous milestone discoveries in the advance of biological sciences. However, the use of biochemical screens aimed at extending the knowledge gained from genetic analysis was explored only recently. Here we describe a method to purify the protein complex that associates with any protein of interest from adult fly heads. This method takes advantage of the Drosophila GAL4/UAS system to express a bait protein fused with a Tandem Affinity Purification (TAP) tag in fly neurons in vivo, and then implements two rounds of purification using a TAP procedure similar to the one originally established in yeast1 to purify the interacting protein complex. At the end of this procedure, a mixture of multiple protein complexes is obtained whose molecular identities can be determined by mass spectrometry. Validation of the candidate proteins will benefit from the resource and ease of performing loss-of-function studies in flies. Similar approaches can be applied to other fly tissues. We believe that the combination of genetic manipulations and this proteomic approach in the fly model system holds tremendous potential for tackling fundamental problems in the field of neurobiology and beyond.

Identifying Protein-protein Interaction in Drosophila Adult Heads by Tandem Affinity Purification TAP

Drosophila is famous for its powerful genetic manipulation, but not for its suitability of in-depth biochemical analysis. Here we present a TAP-based procedure to identify interacting partners of any protein of interest from the fly brain. This procedure can potentially lead to new avenues of research.

Identificando interacção proteína-proteína em<em&gt; Drosophila</em&gt; Chefes Adulto por Tandem Affinity Purification (TAP)

Genetic screens conducted using Drosophila melanogaster (fruit fly) have made numerous milestone discoveries in the advance of biological sciences. ...

Identifying Protein-protein Interaction Sites Using Peptide Arrays

Protein-protein interactions mediate most of the processes in the living cell and control homeostasis of the organism. Impaired protein interactions may result in disease, making protein interactions important drug targets. It is thus highly important to understand these interactions at the molecular level. Protein interactions are studied using a variety of techniques ranging from cellular and biochemical assays to quantitative biophysical assays, and these may be performed either with full-length proteins, with protein domains or with peptides. Peptides serve as excellent tools to study protein interactions since peptides can be easily synthesized and allow the focusing on specific interaction sites. Peptide arrays enable the identification of the interaction sites between two proteins as well as screening for peptides that bind the target protein for therapeutic purposes. They also allow high throughput SAR studies. For identification of binding sites, a typical peptide array usually contains partly overlapping 10-20 residues peptides derived from the full sequences of one or more partner proteins of the desired target protein. Screening the array for binding the target protein reveals the binding peptides, corresponding to the binding sites in the partner proteins, in an easy and fast method using only small amount of protein.
In this article we describe a protocol for screening peptide arrays for mapping the interaction sites between a target protein and its partners. The peptide array is designed based on the sequences of the partner proteins taking into account their secondary structures. The arrays used in this protocol were Celluspots arrays prepared by INTAVIS Bioanalytical Instruments. The array is blocked to prevent unspecific binding and then incubated with the studied protein. Detection using an antibody reveals the binding peptides corresponding to the specific interaction sites between the proteins.

Peptide array screening is a high throughput assay for identifying protein-protein interaction sites. This allows mapping multiple interactions of a target protein and can serve as a method for identifying sites for inhibitors that target a protein. Here we describe a protocol for screening and analyzing peptide arrays.

A identificação da proteína-proteína Locais de interacção Usando Peptide Arrays

Protein-protein interactions mediate most of the processes in the living cell and control homeostasis of the organism. Impaired protein interactions may ...

Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells

Proteins are the building blocks, effectors and signal mediators of cellular processes. A protein&#8217;s function, regulation and localization often depend on its interactions with other proteins. Here, we describe a protocol for the yeast protein-fragment complementation assay (PCA), a powerful method to detect direct and proximal associations between proteins in living cells. The interaction between two proteins, each fused to a dihydrofolate reductase (DHFR) protein fragment, translates into growth of yeast strains in presence of the drug methotrexate (MTX). Differential fitness, resulting from different amounts of reconstituted DHFR enzyme, can be quantified on high-density colony arrays, allowing to differentiate interacting from non-interacting bait-prey pairs. The high-throughput protocol presented here is performed using a robotic platform that parallelizes mating of bait and prey strains carrying complementary DHFR-fragment fusion proteins and the survival assay on MTX. This protocol allows to systematically test for thousands of protein-protein interactions (PPIs) involving bait proteins of interest and offers several advantages over other PPI detection assays, including the study of proteins expressed from their endogenous promoters without the need for modifying protein localization and for the assembly of complex reporter constructs.

Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay PCA in Living Cells

Proteins interact with each other and these interactions determine in a large part their functions. Protein interaction partners can be identified at high-throughput in vivo using a yeast fitness assay based on the dihydrofolate reductase protein-fragment complementation assay (DHFR-PCA).

Genome-wide proteína-proteína Interaction Triagem por proteína-fragmento de Complementação Assay (PCA) em células vivas

Proteins are the building blocks, effectors and signal mediators of cellular processes. A protein&#8217;s function, regulation and localization often ...

Luciferase Complementation Imaging Assay in Nicotiana benthamiana Leaves for Transiently Determining Protein-protein Interaction Dynamics

Protein-protein interactions are fundamental mechanisms for relaying signal transduction in most cellular processes; therefore, identification of novel protein-protein interaction pairs and monitoring protein interaction dynamics are of particular interest for revealing how plants respond to environmental factors and/or developmental signals. A plethora of approaches have been developed to examine protein-protein interactions, either in vitro or in vivo. Among them, the recently established luciferase complementation imaging (LCI) assay is the simplest and fastest method for demonstrating in vivo protein-protein interactions. In this assay, protein A or protein B is fused with the amino-terminal or carboxyl-terminal half of luciferase, respectively. When protein A interacts with protein B, the two halves of luciferase will be reconstituted to form a functional and active luciferase enzyme. Luciferase activity can be recorded with a luminometer or CCD-camera. Compared with other approaches, the LCI assay shows protein-protein interactions both qualitatively and quantitatively. Agrobacterium infiltration in Nicotiana benthamiana leaves is a widely used system for transient protein expression. With the combination of LCI and transient expression, these approaches show that the physical interaction between COP1 and SPA1 was gradually reduced after jasmonate treatment.

Luciferase Complementation Imaging Assay in Nicotiana benthamiana Leaves for Transiently Determining Protein-protein Interaction Dynamics

This manuscript describes an easy and rapid experimental procedure for determining protein-protein interactions based on the measurement of luciferase activity.

Luciferase complementação Imaging ensaio em folhas de Nicotiana benthamiana de transitoriamente determinação dinâmica da interação da proteína-proteína

Protein-protein interactions are fundamental mechanisms for relaying signal transduction in most cellular processes; therefore, identification of novel ...