Laboratuarda çalışma NIH, ABD Tarım Bakanlığı Gıda ve Tarım Ulusal Enstitüsü, NSF, BARD, Enerji Bakanlığı ve BSF VC hibe tarafından desteklenmektedir

1. İfade ve proteinlerin ekstraksiyonu <ol><li> Farklı şekillerde kendi tespiti için test edilmesi proteinler etiketi. Membran (ProIM), daha büyük boyutta (örneğin, GST) bir etiket ile immobilize ve halkaya yapışmamış etiketi hareketsiz bir negatif kontrol (ProIMnc) olarak kullanılabilir protein etiketleyin. Ya büyük ya da küçük bir etiket ile çözünebilir bir prob (ProSOL) olarak kullanılmak üzere protein etiketleyin. Aynı etiket uygun bir negatif kontrol çözünür protein (ProSOLnc) Sigorta ve tespit edilen bağlama özgüllüğü onaylamak için etkileşim tahlil dahil. </li><li> Etiketli proteinleri ifade etmek protein ekspresyon sistemi, yani E. seçin coli, bakülovirüs vb proteinler potansiyel mesaj translasyonel modifikasyonlar ve verim için ihtiyaç bağlı olarak. </li><li> SDS-PAGE proteinaz inhibitörü kokteyl içeren yükleme tamponu (% 20 gliserol,% 4 SDS, 20 mM Tris-HCl, pH6.8) kullanarak seçim organizma (adım 1.2) ProIM ve ProIM nc ayıklayın. Hücre süspansiyonu bırakın, 15 dakika süreyle oda sıcaklığında 2 merkaptoetanol ve 5 dakika boyunca kaynatın% 0.5 &#39;i ekleyin. </li><li> ProSOL ve ProSOL nc, standart protokolleri 16 kullanarak seçim organizma (adım 1.2) ayıklayın . Bu proteinler adım 4.1 (140 mM NaCl, 10 mM Tris-HCl, pH 7.4, 2 mM EDTA, 2 mM DTT,% 1 BSA,% 0.1 Tween 20) bağlayıcı tampon kolayca çözünür olmalıdır. </li><li> Bio-Rad protein tahlil kiti standart bir yöntem kullanılarak rekombinant proteinlerin konsantrasyonu belirleyin. Bio-Rad protein tahlil kiti gibi. Proteinin saflaştırılmış yerine ham özü, tahlil için kullanılması durumunda, Coomassie Brillant Blue R-250 ile ilgili bant densitometrisi SDS-poliakrilamid jel boyanmış ve bilinen kullanarak bu özü ilgi protein konsantrasyonu tahmin referans olarak BSA konsantrasyonları. </li></ol> 2. Membran ProIM ve ProIMnc immobilizasyonu <ol><li> Özler, standart bir protokol 16 göre, SDS-poliakrilamid jel üzerinde ProIM ve ProIM nc 1 mcg içeren her iki takım giderin . </li><li> Elektroforez sonra, 100 ml (60 mM Glisin, 10 mM Tris,% 0.0006 SDS,% 20 MeOH) transfer tampon transferi jel yerleştirin ve yavaşça sallanarak oda sıcaklığında 20 dakika inkübe. </li><li> Nitroselüloz membrana göre standart bir protokol 16 jel bulunan proteinler Electrotransfer. </li></ol> 3. Membrana bağlı proteinler Re-katlama <ol><li> Electrotransfer sonra, 15 dakika için 15 ml tampon membran inkübe A (30 mM Tris-HCl pH7.4,% 0.05 Tween 20) artık SDS kaldırmak için yavaşça sallanarak. </li><li> Dikkatli bir şekilde boşaltılmasının ardından, denatürasyon tampon (7 M guanidin hidroklorür, 2 mM EDTA, 50 mM DTT, 50 mM Tris-HCl, pH 8.3) 25 ml membran aktarın. ve yavaşça sallanarak 2 saat oda sıcaklığında inkübe edin. (Not: denatürasyon tampon inkübe nitroselüloz membran bulanıklaşır). ve yavaşça sallanarak 2 saat oda sıcaklığında inkübe edin. </li><li> 25 TBS ml (10 mM Tris-HCl, 150 mM NaCl, pH 7.4) ve 5 dakika boyunca hafif ajitasyon ile inkübe membran Devret (Not: Bu adım sırasında, orijinal beyaz renkli membran kavuşur). </li><li> Membran bağlayıcı tampon 25 ml (1.2 adım) transferi ve 4 ° C yavaşça sallanarak gece boyunca inkübe edin. </li></ol> 4. ProSOL tarafından ProIM problama <ol><li> Iki şeritler, hem de içeren ProIM ve ProIM nc membran kesin. </li><li> 10 ml taze bağlayıcı tampon ProSOL veya ProSOLnc 1-10 mikrogram ile hazırlık seyreltilmesi ProSOL ve ProSOLnc hibridizasyon çözümleri olun. ProSOL veya ProSOLnc hibridizasyon çözümü her membran transferi ve yavaşça sallanarak oda sıcaklığında 1,5 saat boyunca inkübe edin. </li><li> Hibridizasyon çözümler membranlar çıkarın ve 15 dakika TBS içinde her biri için üç kez yıkayın. </li></ol> 5. Immün protein-protein etkileşim görselleştirme <ol><li> Oda sıcaklığında 1 saat süreyle TBST% 2,5 yağsız süt (10 mM Tris-HCl, 140 mM NaCl,% 0.05 Tween 20, pH 7.4) ile membran engelleyin. TBST% 0,5 yağsız süt üretici tarafından önerilen konsantrasyonda birincil antikor (anti-strepII poliklonal tavşan antikoru) sulandırınız. </li><li> Antikor çözüm bloke membranlar yerleştirin ve oda sıcaklığında 1 saat veya gece boyunca inkübe 4 ° C yavaşça sallanarak. </li><li> 15 dakika için 20 ml TBST membranlar durulayın ve iki kez yavaşça sallanarak oda sıcaklığında 5 dakika. </li><li> TBST% 0,5 yağsız süt üretici tarafından önerilen konsantrasyonda at turp peroksidaz (HRP) ile konjuge sekonder antikoru (anti-tavşan IgG) sulandırınız. Membranlar ikincil antikor yerleştirinçözüm ve yavaşça sallanarak oda sıcaklığında 1 saat süreyle inkübe edin. </li><li> 15 dakika için 20 ml TBST membranlar durulayın ve iki kez yavaşça sallanarak oda sıcaklığında 5 dakika. TBS son durulama sonra, HRP kemilüminesans substrat (örneğin, Millipore Immobilon batı kemilüminesan HRP substrat) kullanarak protein-protein etkileşimleri görselleştirmek. </li><li> 5.4 adımları 5.1 &#39;de açıklanan uygun ikincil antikor takip ProIM, erimiş etiketi için birincil antikor ile aynı membranlar Prob. Görselleştirin ProIM ve ProIMnc protein membran kaplama assay (adım 5.5) elde edilen bantların kimliğini doğrulamak için 5.5 adımı nitelendirdi. Çoğu durumda, bu adımı ile elde edilen sinyal adım 5.5 &#39;ten elde edilen kalıntı sinyali daha güçlü çünkü sıyırma, gerekli değildir. </li></ol> 6. Temsilcisi Sonuçlar: ANK-MP etkileşim tütün epidermal hücreler (Şekil 1A) BiFC gözlendi. MP, bakteri veya bitkilerde ifade yüksek çözünmeyen bir protein olduğu için, protein membran kaplama testi, in vitro (Şekil 1B) bu etkileşimin doğrulamak için kabul edildi. GST-MP (ProIM) veya halkaya yapışmamış GST (ProIM nc) 1 mg protein özleri içeren bir nitroselüloz membran electrotransfer takip SDS-poliakrilamid jel elektroforezi, çözüldü. Bu ProIMs çözünür ANK-strepII (ProSOL), GST-MP, ancak halkaya yapışmamış değil GST probed bağlayıcı sergilenmektedir (Şekil 1B, hat 1, 2, 5, 6 şeritli karşılaştırın). Ayrıca, aynı ProIMs ANK-MP etkileşim özgüllüğü (Şekil 1B, daha gösteren bir ilgisi olmayan ProSOLnc, yani strepII (NADH3-strepII) etiketli Arabidopsis sitoplazmik NADH kinaz, hiçbir bağlayıcı gözlenmemiştir ile probed şerit 3, 4). <img src="/files/ftp_upload/2961/2961fig1.jpg" alt="Şekil 1"/> Şekil 1, in vivo ve in vitro TMV MP tütün ANK Özgül bağlayıcıdır . (A), BiFC tarafından tespit edilen tütün epidermal hücrelerin yaşam ANK-MP etkileşim. MP ve ANK, C-terminal ve sırasıyla YFP N-terminal yarısı erimiş Güçlü YFP sinyali kodlayan genlerin microbombardment tütün epidermiste coexpressed, yeniden inşa edildi. Bu BiFC sinyal plasmodesmata 15 tanı hücre çevre, puncta birikmiş. (B) in vitro ANK-MP etkileşim gibi protein membran kaplama yöntemi ile tespit edildi. GST-MP (ProIM) veya halkaya yapışmamış GST (ProIMnc) 1 mg protein özleri içeren bir nitroselüloz membran üzerine electrotransfer% 15 SDS-poliakrilamid jel, çözüldü. GST-MPProIM ve GSTProIMnc ANK-strepII (ProSOL) 0.5 mg / ml ile inkübe edildi ve ANK bağlama konjuge anti-tavşan IgG + M sekonder antikoru, anti-strepII tavşan poliklonal antikor ile membran problama tespit edildi HRP (1 ve 2 şeritli). GST-MPProIM ne GSTProIMnc ne strepII etiketi (ProSOLnc, şerit 3 ve 4) erimiş alakasız bir protein, Arabidopsis sitoplazmik NADH kinaz ile etkileşim. Bu testte gözlenen grubun kimliğini anti-GST antikor (şerit 5 ve 6) ile membran problama tarafından teyit edildi. ANK-strepII GST-MP ve GST contining protein özleri bulunan kimliği belirsiz proteinler ile reaksiyona membran tampon A ile yıkanır olmadan denatürasyon tamponu ile tedavi edildi, GST-MP ANK bağlama önemini gösteren, kaybolur 3.1 adım önce denatürasyon süreci (şerit 7 ve 8).

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Çıkar çatışması ilan etti.

Bu yaklaşım, proteinler en az bağlayıcı tampon kolayca çözünür olduğu ve diğer proteinlerin kombinasyonu 17,18 başarıyla uygulandı proteinler kombinasyonları arasında protein-protein etkileşimleri, test etmek için uygundur . Bu koşullar altında hem de çözünmez proteinler arasındaki iInteractions Bu protokol tarafından test edilemez. Ayrıca, başarılı refolding ProIM testi için kritik öneme sahiptir. Kalan SDS denatürasyon / Yeniden doğallaştırman?...

<table border="1"><tbody><tr><td> Reaktifin Adı </td><td> Şirket </td><td> Katalog numarası </td></tr><tr><td> Protein tahlil kiti </td><td> Bio-Rad </td><td> 500-0001 </td></tr><tr><td> Proteinaz inhibitörü kokteyl </td><td> SIGMA </td><td> S8820 </td></tr><tr><td> Mini-Protean sistemi </td><td> Bio-RAD </td><td> 165-8000 </td></tr><tr><td> Yarı kuru western blot SD electrotransfer sistemi </td><td> Bio-RAD </td><td> 170-3940 </td></tr><tr><td> At turp peroksidaz ile konjuge anti-tavşan IgG </td><td> GenScript </td><td> A00098 </td></tr><tr><td> Anti-GST tavşan poliklonal antikor </td><td> GenScript </td><td> A00097 </td></tr><tr><td> Anti-strepII </td><td> GenScript </td><td> A00626 </td></tr><tr><td> Biotrace, NT nitroselüloz transferi membran </td><td> Pall Bilimsel </td><td> 27377-000 </td></tr><tr><td> Immobilon batı kemilüminesan HRP substrat </td><td> Millipore </td><td> WBKL S0 050 </td></tr></tbody></table>

protein membrane overlay assay: a protocol to test interaction between soluble and insoluble proteins in vitro

Validating farklı proteinler arasındaki etkileşimleri, moleküler düzeyde kendi biyolojik fonksiyonları incelenmesi için hayati önem taşımaktadır. Proteine ​​bağlanma in vitro ve in vivo olarak değerlendirmek için, çeşitli yöntemler vardır ve birbirlerinin eksikliklerini tamamlayacak en az iki yöntem güvenilir bilgiler elde etmek için yapılmalıdır. In vivo tayininde, iki moleküllü floresan tamamlama (BiFC) tayini, canlı hücre içerisinde protein-protein etkileşimleri algılamasını sağlar en popüler ve en az invaziv bir yaklaşımı temsil ediyor, hem de etkileşen proteinler 1,2, hücre içi lokalizasyonu belirlemek için. Bu testte, GFP veya türevleri olmayan floresan K ve C-terminal yarıya iki füzyon proteinleri test proteinler &#39;etkileşimleri nedeniyle bir araya getiren ne zaman test proteinler erimiş, ve floresan sinyal 3-6 sulandırılmış. . Çünkü sinyali Epifloresans veya konfokal mikroskobu ile kolayca tespit edilebilir, BiFC hücre biyologlar arasında seçim canlı hücreler 3 protein-protein etkileşimleri hakkında eğitim için güçlü bir araç olarak ortaya çıkmıştır. Bu testte, ancak, bazen yalancı pozitif sonuç üretebilir. Örneğin, floresan sinyal daha ziyade bu spesifik etkileşimler nedeniyle 7, küçük bir hücre içi kompartmanda ambalaj yakın nedeniyle her bildiğim kadarıyla 7 nm düzenlenmiş iki GFP parçaları ile sulandırılmış olabilir. Bu sınırlamalar nedeniyle, canlı hücre görüntüleme teknolojilerinden elde edilen sonuçlar, protein etkileşimleri tespit etmek için farklı bir prensip dayalı bağımsız bir yaklaşım tarafından teyit edilmelidir. Co-immunoprecipitation (Co-IP) ya da glutatyon transferaz (GST) açılan deneyleri, in vitro protein-protein etkileşimleri analiz etmek için yaygın olarak kullanılır gibi alternatif yöntemler temsil eder. Ancak, bu testlerin iin, ancak, test edilen proteinleri bağlama reaksiyon supportsused tampon kolayca çözünür olmalıdır. Bu nedenle, spesifik etkileşimler çözünmeyen bir protein içeren bu tekniklerin tarafından değerlendirilmelidir. Burada, biz bu zorluğu circumvents protein membran kaplama bağlayıcı testi için protokol göstermektedir. Bu teknikte, çözünür ve çözünmez proteinler arasındaki etkileşim, bir zar matriks proteinleri biri üzerinde hareketsiz çünkü güvenilir bir şekilde test edilebilir. Bu yöntem, in vivo deneyler, bu tür BiFC ile birlikte, sadakatle çözünür ve çözünmez proteinler arasındaki etkileşimleri incelemek ve karakterize etmek için güvenilir bir yaklaşım sağlar. Bu makalede, Tütün mozaik virüsü (TMV) arasında viral hücre-hücre 8-14 taşıma sırasında birden çok işlevi uygular hareket protein (MP), ve kısa bir süre önce tanımlanmış bitki hücresel interactor, tütün ankyrin tekrar içeren protein bağlama (ANK 15), bu tekniği kullanarak gösterilmiştir.

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Protein Membrane Overlay Assay: A Protocol to Test Interaction Between Soluble and Insoluble Proteins in vitro

Test protein-protein etkileşim protein işlevsellik diseksiyon için vazgeçilmezdir. Burada, bir tanıtmak<em&gt; In vitro</emÇözünen bir protein ile bir zar hareketsiz protein prob&gt; protein-protein bağlayıcı tahlil. Bu testte, çözünmeyen bir protein ve çözüm bir protein arasındaki ilişkiyi test etmek için güvenilir bir yöntem sağlar.

Protein Membran Kaplama Testi: Çözünür ve çözünmez Proteinler Arasında Etkileşim Test Protokolü In vitro</em

Validating interactions between different proteins is vital for investigation of their biological functions on the molecular level.  There are several ...

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Protein Membrane Overlay Assay: A Protocol to Test Interaction Between Soluble and Insoluble Proteins in vitro

22.0K Görüntüleme.  State University of New York. Test protein-protein etkileşim protein işlevsellik diseksiyon için vazgeçilmezdir. Burada, bir tanıtmak In vitro protein-protein bağlayıcı tahlil. Bu testte, çözünmeyen bir protein ve çözüm bir protein arasındaki ilişkiyi test etmek için güvenilir bir yöntem sağlar.

Video: Protein Membrane Overlay Assay: A Protocol to Test Interaction Between Soluble and Insoluble Proteins in vitro

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.

Organik Solvent ve Asetik Asit olmadan Jeller Coomassie G-250 ile Proteinlerin Boyama

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

Biyoloji

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)

Helios Gen Tabancası kullanarak Soğan Hücrelerde Protein-Protein Etkileşimi Bimoleküler Floresan tamamlama (BiFC) Testi

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

A Liquid Phase Affinity Capture Assay Using Magnetic Beads to Study Protein-Protein Interaction: The Poliovirus-Nanobody Example

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. Provided that one protein can be tagged and another protein labeled, this method can be implemented for the investigation of protein-protein interactions. It is based on one hand on the recognition of the tagged protein by cobalt coated magnetic beads and on the other hand on the interaction between the tagged protein and a second specific protein that is labeled. First, the labeled and tagged proteins are mixed and incubated at room temperature. The magnetic beads, that recognize the tag, are added and the bound fraction of labeled protein is separated from the unbound fraction using magnets. The amount of labeled protein that is captured can be determined in an indirect way by measuring the signal of the labeled protein remained in the unbound fraction. The described liquid phase affinity assay is extremely useful when conformational conversion sensitive proteins are assayed. The development and application of the assay is demonstrated for the interaction between poliovirus and poliovirus recognizing nanobodies1. Since poliovirus is sensitive to conformational conversion2 when attached to a solid surface (unpublished results), the use of ELISA is limited and a liquid phase based system should therefore be preferred. An example of a liquid phase based system often used in polioresearch3,4 is the micro protein A-immunoprecipitation test5. Even though this test has proven its applicability, it requires an Fc-structure, which is absent in the nanobodies6,7. However, as another opportunity, these interesting and stable single-domain antibodies8 can be easily engineered with different tags. The widely used (His)6-tag shows affinity for bivalent ions such as nickel or cobalt, which can on their turn be easily coated on magnetic beads. We therefore developed this simple quantitative affinity capture assay based on cobalt coated magnetic beads. Poliovirus was labeled with 35S to enable unhindered interaction with the nanobodies and to make a quantitative detection feasible. The method is easy to perform and can be established with a low cost, which is further supported by the possibility of effectively regenerating the magnetic beads.

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. It is a reliable technique based on the interaction between magnetic beads and tagged proteins (e.g. nanobodies) on one hand and the affinity between the tagged protein and a second, labeled protein (e.g. poliovirus) on the other.

Protein-Protein Etkileşimi Okumak Manyetik Boncuk Kullanarak Bir Sıvı Faz Affinity Yakalama Testi: Poliovirüs-Nanobody Örnek

In this article, a simple, quantitative, liquid phase affinity capture assay is presented. Provided that one protein can be tagged and another protein ...

Use of a Robot for High-throughput Crystallization of Membrane Proteins in Lipidic Mesophases

Structure-function studies of membrane proteins greatly benefit from having available high-resolution 3-D structures of the type provided through macromolecular X-ray crystallography (MX). An essential ingredient of MX is a steady supply of ideally diffraction-quality crystals. The in meso or lipidic cubic phase (LCP) method for crystallizing membrane proteins is one of several methods available for crystallizing membrane proteins. It makes use of a bicontinuous mesophase in which to grow crystals. As a method, it has had some spectacular successes of late and has attracted much attention with many research groups now interested in using it. One of the challenges associated with the method is that the hosting mesophase is extremely viscous and sticky, reminiscent of a thick toothpaste. Thus, dispensing it manually in a reproducible manner in small volumes into crystallization wells requires skill, patience and a steady hand. A protocol for doing just that was developed in the Membrane Structural &amp; Functional Biology (MS&amp;FB) Group1-3. JoVE video articles describing the method are available1,4. 
The manual approach for setting up in meso trials has distinct advantages with specialty applications, such as crystal optimization and derivatization. It does however suffer from being a low throughput method. Here, we demonstrate a protocol for performing in meso crystallization trials robotically. A robot offers the advantages of speed, accuracy, precision, miniaturization and being able to work continuously for extended periods under what could be regarded as hostile conditions such as in the dark, in a reducing atmosphere or at low or high temperatures. An in meso robot, when used properly, can greatly improve the productivity of membrane protein structure and function research by facilitating crystallization which is one of the slow steps in the overall structure determination pipeline. 
In this video article, we demonstrate the use of three commercially available robots that can dispense the viscous and sticky mesophase integral to in meso crystallogenesis. The first robot was developed in the MS&amp;FB Group5,6. The other two have recently become available and are included here for completeness.	
An overview of the protocol covered in this article is presented in Figure 1. All manipulations were performed at room temperature (~20 &deg;C) under ambient conditions.

Herein is described a robotic approach to high-throughput crystallization of membrane proteins in lipidic mesophases for use in structure determination using macromolecular X-ray crystallography. Three robots capable of handling the viscous and sticky protein-laden mesophase integral to the method are introduced.

Lipidik Mesophases Membran Proteinleri Yüksek throughput Kristalizasyon için bir robot kullanımı

Structure-function studies of membrane proteins greatly benefit from having available high-resolution 3-D structures of the type provided through ...

In vitro Methylation Assay to Study Protein Arginine Methylation

Protein arginine methylation is one of the most abundant post-translational modifications in the nucleus. Protein arginine methylation can be identified and/or determined via proteomic approaches, and/or immunoblotting with methyl-arginine specific antibodies. However, these techniques sometimes can be misleading and often provide false positive results. Most importantly, these techniques cannot provide direct evidence in support of the PRMT substrate specificity. In vitro methylation assays, on the other hand, are useful biochemical assays, which are sensitive, and consistently reveal if the identified proteins are indeed PRMT substrates. A typical in vitro methylation assay includes purified, active PRMTs, purified substrate and a radioisotope labeled methyl donor (S-adenosyl-L-[methyl-3H] methionine). Here we describe a step-by-step protocol to isolate catalytically active PRMT1, a ubiquitously expressed PRMT family member. The methyl transferase activities of the purified PRMT1 were later tested on Ras-GTPase activating protein binding protein 1 (G3BP1), a known PRMT substrate, in the presence of S-adenosyl-L-[methyl-3H] methionine as the methyl donor. This protocol can be employed not only for establishing the methylation status of novel physiological PRMT1 substrates, but also for understanding the basic mechanism of protein arginine methylation.

In vitro Methylation Assay to Study Protein Arginine Methylation

Protein arginine methylation, catalyzed by a class of enzymes viz., protein arginine methyl transferases (PRMTs), is the process of enzymatic addition of methyl group(s) to arginines within proteins. The in vitro methylation assay is the most dependable tool for assessing the methylation status of known or novel PRMT substrates.

In vitro Metilasyona Tahlil Protein Arginin metilasyon Okuyacak

Protein arginine methylation is one of the most abundant post-translational modifications in the nucleus. Protein arginine methylation can be identified ...

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).

Yaşayan Hücrelerde Protein-fragmanı tamamlama Assay (PCA) ile genom Protein-protein etkileşimi Eleme

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

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and the inherent instability of many membrane proteins once solubilized in detergents. A protocol is described that combines ligation independent cloning of membrane proteins as GFP fusions with expression in Escherichia coli detected by GFP fluorescence. This enables the construction and expression screening of multiple membrane protein/variants to identify candidates suitable for further investment of time and effort. The GFP reporter is used in a primary screen of expression by visualizing GFP fluorescence following SDS polyacrylamide gel electrophoresis (SDS-PAGE). Membrane proteins that show both a high expression level with minimum degradation as indicated by the absence of free GFP, are selected for a secondary screen. These constructs are scaled and a total membrane fraction prepared and solubilized in four different detergents. Following ultracentrifugation to remove detergent-insoluble material, lysates are analyzed by fluorescence detection size exclusion chromatography (FSEC). Monitoring the size exclusion profile by GFP fluorescence provides information about the mono-dispersity and integrity of the membrane proteins in different detergents. Protein: detergent combinations that elute with a symmetrical peak with little or no free GFP and minimum aggregation are candidates for subsequent purification. Using the above methodology, the heterologous expression in E. coli of SED (shape, elongation, division, and sporulation) proteins from 47 different species of bacteria was analyzed. These proteins typically have ten transmembrane domains and are essential for cell division. The results show that the production of the SEDs orthologues in E. coli was highly variable with respect to the expression levels and integrity of the GFP fusion proteins. The experiment identified a subset for further investigation.

Green Fluorescent Protein-based Expression Screening of Membrane Proteins in Escherichia coli

A streamlined approach to screening for the expression of recombinant membrane proteins in Escherichia coli based on fusion to green fluorescent protein is presented.

Membran proteinlerinin Yeşil floresan proteini temelli Ekspresyon elemesinde<em&gt; Escherichia coli</em

The production of recombinant membrane proteins for structural and functional studies remains technically challenging due to low levels of expression and ...

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 tamamlayıcı Imaging tahlil Nicotiana benthamiana yaprakları Protein-protein etkileşim Dynamics geçici belirlenmesi için

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

Determination of Tripartite Interaction between Two Monomers of a MADS-box Transcription Factor and a Calcium Sensor Protein by BiFC-FRET-FLIM Assay

Protein-protein interactions are an integral part of all biological processes in the cells as they play a crucial role in regulating, maintaining, and amending cellular functions. These interactions are involved in a wide range of phenomena such as signal transduction, pathogen response, cell-cell interactions, metabolic and developmental processes. In the case of transcription factors, these interactions may lead to oligomerization of subunits, sequestering in specific subcellular contexts such as the nucleus, cytoplasm, etc., which, in turn, might have a more profound effect on the expression of the downstream genes. Here, we demonstrate a methodology to visualize in vivo tripartite interaction using Bimolecular Fluorescence Complementation (BiFC) based F&#246;rster Resonance Energy Transfer (FRET) involving Fluorescence Lifetime Imaging (FLIM). Two of the proteins selected for this demonstration interact as BiFC partners, and their reconstituted fluorescence activity is used to assay FRET-FLIM with the third partner. Four to five-week-old growth-chamber-grown Nicotiana benthamiana plants have been used as the model plant system for this demonstration.

Here we present, a method to visualize ternary complex formation between three protein partners using fluorescent-tagged proteins by BiFC based FRET-FLIM assay. This method is valuable for studying protein-protein interaction complexes in vivo.

BiFC-FRET-FLIM Tahlilinde MADS Kutusu Transkripsiyon Faktörünün İki Monomeri ile Kalsiyum Sensör Proteini Arasındaki Üçlü Etkileşimin Belirlenmesi

Protein-protein interactions are an integral part of all biological processes in the cells as they play a crucial role in regulating, maintaining, and ...

E. coli'den Rekombinant Protein Dolu Veziküllerin Üretimi ve Görüntülenmesi

Optimized Production and Analysis of Recombinant Protein-Filled Vesicles from E. coli

This innovative system, using a short peptide tag, that exports multiple recombinant proteins in membrane bound vesicles from E. coli, provides an effective solution to a range of problems associated with bacterial recombinant protein expression. These recombinant vesicles compartmentalise proteins within a micro-environment that facilitates the production of otherwise challenging, toxic, insoluble, or disulfide-bond containing proteins from bacteria. Protein yield is increased considerably when compared to typical bacterial expression in the absence of the vesicle-nucleating peptide tag. The release of vesicle-packaged proteins supports isolation from the culture medium&#160;and permits long-term active protein storage. This technology gives rise to increased yields of vesicle-packaged, functional proteins for simplified downstream processing for a diverse range of applications from applied biotechnology to discovery science and medicine. In the present article and the associated video, a detailed protocol of the method is provided, which highlights key steps in the methodology to maximize recombinant protein-filled vesicle production.

Yazar Spotlight: Rekombinant Proteinlerin Üretimi 

The present protocol describes a detailed method for the bacterial production of recombinant proteins, including typically insoluble or disulfide-bond containing proteins, packaged inside extracellular membrane-bound vesicles. This has the potential to be applied to versatile areas of scientific research, including applied biotechnology and medicine.