Biz yönteminin gelişmesine yol açan tartışmalar için Anne-Marie Dion-Cote teşekkür ederim. JK ve RB FQNRT doktora alimler vardır, M.-MG Vanier CIHR âlimi, ve J.-YM bir FRSQ kıdemli araştırmacıdır. Bu çalışma, Fen Bilimleri ve JY Mühendislik Araştırma Konseyi fonları tarafından desteklenmiştir. M.

1.. Rekombinan bakulovirüslerin üretimi Bakulovirüsler esas olarak sadece hafif bir değişiklik ile, üreticinin protokolüne uygun olarak Invitrogen&#39;in Bac-to-Bac Baculovirus Expression System kullanılarak üretilir: <ol><li> Bir modifiye pFastBac1 vektörü (Gibco, yaşam) GST ve O&#39;nun etiketleri (Şekil 2) içeren oluşturuldu. PET-52b (+) vektörü (Novagen) multiklonlama bölgesine (MCS), bir 10xHis-etiketi ihtiva eden, pFastBac1-Strep-10xHis oluşturmak için bir pFastBac1 vektörünün MCS sokulmuştur. PET-52b (+) MCS dizisi 5 &#39;ucunda bir BglII kısıtlama sitesi&#39; ucu ve 3 &#39;bölgesinde bir Hind III sınırlandırma sitesi&#39; ucuna eklenmesi, Xbal ve HBLP kısıtlayıcı siteleri arasında amplifiye PCR oldu. PCR ürünü daha sonra BamHI ve BglII kısıtlama dizilerin uyumluluk kullanılarak BamHI ve Hindlll kısıtlama pFastBac1 sitesi arasında klonlandı. Amaç ifade sağlayan bir pFastBac1 oluşturmak için olduğu içinve streptavidin-10xHis etiketleri ile rekombinant protein, pET-52b (+) BamHI kısıtlama alanı MCS sekansı kullanılmadı. Ayrıca, Xbal kısıtlama alanı zaten pFastBac1 bir MCS ve pET-52b MCS ile eklenen, bu (+) &#39;de siteler arasında meydana gelen kısıtlama sitelerinin fazlalık önlemek için kullanılmamıştır. PreScisson Proteaz tanıma sitesi (LeuGluValLeuPheGln / GlyPro) ile GST kodlayıcı sekans daha sonra pFastBac1-Strep-10xHis içine sokulmuştur. PGEX-6P-2 (GE Healthcare) için GST cDNA sekansı PCR sırasıyla 5 de, Ncol ve Kpnl sınırlandırma bölgelerini içeren bir primer &#39;ve 3&#39; ekstremite ile büyütülmüştür. Ncol mevkisi bir başlangıç ​​kodonu ve buna ek olarak değil, aynı zamanda bir GST Alanin sağlar. PCR ürünü daha sonra streptavidin-etiketinin silinmesi ile sonuçlanan, Ncol ve Kpnl kısıtlama siteleri arasında pFastBac1-Strep-10xHis klonlanmıştır. Bu şekilde elde edilen yeni bir füzyon vektörü pFastBac1-GST-10xHis seçildi. </li><li> Pr için cDNA kodlama CloneGST (N-terminal) ve His-etiketi (C-ucu) arasındaki pFastBac-GST-10xHis vektörü içine ilgi otein. C-terminal His-tag ile füzyon izin vermek için cDNA durdurma kodonunu ortadan kaldırmak için dikkat edin. </li><li> E. Transform (Adım 1.2 &#39;de elde edilmiştir) rekombinant pFastBac ile coli DH10Bac bacmid üretir. Koloniler Bluo-gal ve IPTG (10 ug / ml tetrasiklin, 50 ug / ml kanamisin, 7 ug / ml gentamisin, 100 ug / ml Bluo-ihtiva-eden seçme plakaları üzerinde 30 ° C &#39;de 37 ° C ve birkaç saat gece boyunca büyümeye izin verin Gal, 40 ug / ml IPTG). </li><li> Seçim ve beyaz fenotip onaylamak için seçme plakaları üzerinde (adım 1.3) 2 beyaz koloniler restreak. </li><li> 10 ug / ml tetrasiklin, 50 ug / ml kanamisin, 10 ug / ml gentamisin aşama 1.4 &#39;dan iki beyaz koloniler ile ve bunların 37 ° C de bir gece boyunca çalkalama altında (250 rpm) büyümesine izin ihtiva eden LB içinde 2 ml inoküle </li><li> Bacmid DNA&#39;yı saflaştırmak amacıyla, aşama 1.5 bakterileri peletçözeltisi 300 ul I hücreleri tekrar süspansiyon ve çözelti II 300 ul (Qiagen&#39;den Maksiprep kit) ekleyin. , Oda sıcaklığında 5 dakika boyunca inkübe 3 M KOAc, pH 5.5 içinde 300 ul ekleyin ve buz üzerinde 10 dakika inkübe edilir. 4 ° C, 10 dakika boyunca yüksek hızda örnekleri santrifüj. Yüzer için izopropanol 800 ul eklenir ve buz üzerinde 10 dakika inkübe edilir. 4 ° C&#39;de 15 dakika boyunca santrifüj örnekleri ve% 70 etanol içinde 500 ul ile pelet yıkayın. Pelet kuruması ve Tris-EDTA pH 8.0, 40 ul steril koşullar altında yeniden süspanse edin. Bacmid DNA, 4 ° C &#39;de muhafaza edilmelidir </li><li> Üreticinin protokolünde tarif edildiği gibi baculovirüsler oluşturmak. Bakulovirüsler ışıksız bir ortamda 4 ° C&#39;de saklanabilir. </li></ol> 2. Rekombinant Protein Expression <ol><li> Arıtma için en verimli bakülovirüsü seçmek ve protein ifade zirve ulaşıldığında ne zaman izlemek için bir mini-enfeksiyon deneyi a gerçekleştirmeks aşağıdaki gibidir: 2 Sf9 x 10 7 bakulovirüsün 133 ul (1/150) ile (% 10 FBS ve% 1 P / S ile tamamlanır) Grace ortam içinde 27 ° C &#39;de kültür hücreleri enfekte Infect. 0, 24, 48, 1.5 ml&#39;lik alikotları toplamak ve 72 saat post-enfeksiyon. Pelet hücreleri ve anti-tag antikoru kullanılarak western blotting ile, ilgi konusu proteinin ekspresyonu düzeyini analiz. </li><li> Virüs ve ortam arasında 1/150 oranı ile bir ortamın 500 ml, ml başına 1.0 x 10 6 Sf9 hücrelerini içeren bir değer değiştirici enfekte etmek için aşama 2.1 &#39;den en verimli bakulovirüs kullanın. Enfekte olan hücreler, 27 ° C &#39;de süspansiyon içinde büyümeye ve en yüksek protein ekspresyon (yukarıdaki aşama 2.1&#39; de tespit edildiği üzere) ulaşıldığında hücreleri hasat olsun. Tanelenmiş hücreler daha fazla kullanıma kadar -80 ° C&#39;de muhafaza edilebilir. </li></ol> 3. Çözünür hücre lisatı hazırlanması Aşağıdaki kuluçka adımlarının tüm hafif dönme altında 4 ° C&#39;de gerçekleştirilmektedir. <ol><li> Lyse SGST bağlayıcı tampon (150 mM NaCl, 1 mM EDTA,% 0.05 Triton-X-100, 1 mM 250 mM NaCI nihai konsantrasyon için PBS1X de DTT ve proteaz inhibitör ~ 20 ml ilgi proteini eksprese eden hücreler f9 kokteyli (Roche). bir buzlu su banyosu içinde, bir Dounce homojenleştirici, sonikasyon 3x 30 saniye her biri (% 70 üretim) ile çözeltinin Dounce 20x ve 20x yeniden Dounce. </li><li> (İsteğe bağlı). DNA ya da RNA kontaminasyonu çıkarmak için 4 ° C&#39;de 30 dakika boyunca 1 mM MgCI2 ve 7 nükleaz (2.5 U / ml) benzonaz toplam hücre lizatı inkübe edin. </li><li> 4 ° C&#39;de 30 dakika boyunca 18,000 rpm&#39;de santrifüje Süpernatant tutun. </li><li> (İsteğe bağlı). Santrifüj süpernatan tekrar 4 ° C&#39;de 18,000 rpm&#39;de 30 dakika boyunca berrak lizat çözünür alır. Tıkanmasını önlemek için, 0.2 ya da 0.45 um&#39;lik bir filtreden süpernatantı geçirir. </li></ol> 4. GST Boncuk Protein bağlanması <ol><li> GST boncuk 1 ml Çözünür hücre lisatı inkübe (iki kez yıkanmışGST 10 mi yumuşak döndürülerek 4 ° C&#39;de 1 saat boyunca tamponu) bağlayıcı. </li></ol> Yorum: Kuluçka süresi, proteinin stabilite ve bağlanma verimliliği göre optimize edilmesi gerekmektedir. <ol start="2"><li> Hızlı 700 rpm&#39;de spin ve ilişkisiz proteinleri içeren süpernatant kaldırmak (bu daha fazla analiz için muhafaza edilebilir). GST Yıkama tamponu ile GST-bağlı protein (Şekil 3B, şerit 1) yıkayın (GST 350 mM NaCl finali ile bağlama tamponu). </li><li> Adımı tekrarlayın 4.2 2x. Son yıkamadan olarak, mümkün olduğu kadar supernatant çıkarın. </li><li> Isı-şok proteinleri 8 arasında spesifik olmayan bağlanmanın olmaması için 4 ° C&#39;de 1 saat boyunca (10 mi GST bağlama tamponu içinde) 5 mM ATP ve 15 mM MgCl2 ile boncuk inkübe edin. GST yıkama tamponu ile boncuk üç kez yıkayın. </li></ol> 5. GST PreScisson Dilinim <ol><li> GST boncuk santrifüj, süpernatant kaldırmak ve P5 buf ile GST boncuk yıkayınfer (50 mM NaHPO 4 pH 7.0, 500 mM NaCl,% 10 gliserol,% 0.05 Triton-X-100, 5 mM imidazol). </li><li> 3 saat için gece boyunca 4 ° C den P5 tamponu PreScisson enzimi ile GST-boncuk inkübe (100 ul fraksiyon olarak GST boncuk bölün ve P5 tampon 100 ul seyreltilmiş enzim, 4-8 adet (2-4 ul) ekleyin.) </li></ol> Yorum: PreScisson aşamasının Kuluçka süresi molekül ağırlığı hem de protein kararlılığına göre optimize edilmesi gerekmektedir. Bozunma görülmektedir, bu, bir gece boyunca inkübasyon süresi, 2 saat içinde en az yerine göre azaltılabilir. <ol start="3"><li> Hızlı spin ve süpernatant toplamak. P5 100 ul ekleyerek sonra bu adımı iki kez tekrarlayın boncuklara tampon ve tüm kısımlar (Şekil 3B, şerit 2) havuz. </li></ol> Yorum: Kalan boncuklar bölünme etkinliğinin analizi için kullanılabilir (Şekil 3B </strong&gt;, şerit 3). Genellikle, proteinin% 70-80 bölünmektedir. 6. Protein bağlayıcı TALON Metal Afinite Reçine&#39;ye <ol><li> 1 ml&#39;lik fraksiyonlar halinde 3 yukarıdan elüsyon bölün ve döndürme altında 1 saat boyunca (P5 tamponu ile iki kez yıkanmış) 100 ul Talon metal afinite reçinesi ile kuru boncuk her inkübe edin. </li></ol> Yorum: Bir çok paylarda elüsyon bölme bağlayıcı / yıkama verimliliği artırır. <ol start="2"><li> P30 tamponu (30 mM imidazol, son konsantrasyon ile P5 tamponu) ile reçine 5 dakika yıkanır. </li><li> Adımı 6.2 2x tekrarlayın ve tek bir tüp içinde boncuk havuzu. Son yıkamadan önce, mümkün olduğu kadar supernatant çıkarın. </li></ol> Yorum: Bu TALON bağlı numune (Şekil 3B, şerit 4) karşılık gelmektedir. 7. Saflaştırılmış Protein elüsyonu <ol><li> P5 ile birlikte dönüş altında 5 dakika için protein bağlı TALON reçine inkübe00 tampon maddesi (500 mM imidazol, son konsantrasyon ile P5 tamponu). Tampon ve 01:01 h / h arasında boncuklar arasında bir oranı kullanarak (Eğer kuru boncuk 200 ul almıştı Örneğin, siz P500 200 ul eklemek gerekir). Bu adımı iki kez tekrarlayın ve ayrı ayrı her akıtılan kısmını tutmak (; Şekil 3B, 5-7 kuşak), yıkama 1 (E1) adında yıkama 2 (E2 ve elüsyon 3 (E3)). </li></ol> Yorum: Kalan boncuk elüsyon verimi (Şekil 3B, şerit 8) analizi için kullanılabilir. Tipik haliyle, proteinin% 60-80 toplam akıtılır. <ol start="2"><li> Coomassie mavisi (Şekil 3B) veya görüntüleme için SYPRO protein boyası ile bir SDS-PAGE ve leke üzerinde standart BSA konsantrasyonu her fraksiyonun yaklaşık 20-40 ul yükleme göre saflaştırılmış protein miktarını ve kalitesini analiz edin. </li></ol> Yorum: İlgilenilen proteini aynı zamanda bir uçtan bir uca tespit edilebiliranti-GST ve anti-His antikorları (Şekil 3C) kullanılarak saflaştırma prosedürü hayatları boyunca. 8. Saflaştırılmış proteinin depolanması <ol><li> 4 ° C sıcaklıkta, uygun bir saklama tamponu ile saflaştırılmış proteinin (örneğin 20 mM Tris asetat pH 8.0, 200 mM KAc,% 10 gliserol, 1 mM EDTA, 0.5 mM DTT) Dialyze Bu, diyaliz sırasında, saflaştırılmış proteinin çökeltilmesi için kontrol etmek önemlidir. Genellikle çalkalama döndürme altında 4 ° C&#39;de 1 saat boyunca 2x dialyze. </li><li> Saflaştırılmış protein (10-20 ul) az miktar yapın ve 30 dakika boyunca kuru buz üzerinde dondurma. -80 ° C&#39;de alikotları saklamak ve birçok çözülme / donma döngüleri kaçının. </li></ol>

<ol>
	<li>Lichty, J. J., Malecki, J. L., Agnew, H. D., Michelson-Horowitz, D. J., Tan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+affinity+tags+for+protein+purification.">Comparison of affinity tags for protein purification.</a> Protein Expr. Purif. 41, 98-105 (2005).</li><li>Thain, A., Gaston, K., Jenkins, O., Clarke, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+the+separation+of+GST+fusion+proteins+from+co-purifying+GroEL.">A method for the separation of GST fusion proteins from co-purifying GroEL.</a> Trends Genet. 12, 209-210 (1996).</li><li>Carr, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+a+recombinant+form+of+the+V+antigen+of+Yersinia+pestis,+using+three+different+expression+systems.">Expression of a recombinant form of the V antigen of Yersinia pestis, using three different expression systems.</a> Vaccine. 18, 153-159 (1999).</li><li>Armisen, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+adsorption+of+poly-His+tagged+glutaryl+acylase+on+tailor-made+metal+chelate+supports.">Selective adsorption of poly-His tagged glutaryl acylase on tailor-made metal chelate supports.</a> J. Chromatogr. A. 848, 61-70 (1999).</li><li>Kuhn, S., Zipfel, P. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+baculovirus+expression+vector+pBSV-8His+directs+secretion+of+histidine-tagged+proteins.">The baculovirus expression vector pBSV-8His directs secretion of histidine-tagged proteins.</a> Gene. 162, 225-229 (1995).</li><li>Buisson, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cooperation+of+breast+cancer+proteins+PALB2+and+piccolo+BRCA2+in+stimulating+homologous+recombination.">Cooperation of breast cancer proteins PALB2 and piccolo BRCA2 in stimulating homologous recombination.</a> Nat. Struct. Mol. Biol. 17, 1247-1254 (2010).</li><li>Filimonova, M. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isoforms+of+Serratia+marcescens+nuclease.+The+role+of+Mg2++in+the+hydrolysis+mechanism.">Isoforms of Serratia marcescens nuclease. The role of Mg2+ in the hydrolysis mechanism.</a> Biochemistry. 62, 983-988 (1997).</li><li>Thorslund, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+breast+cancer+tumor+suppressor+BRCA2+promotes+the+specific+targeting+of+RAD51+to+single-stranded+DNA.">The breast cancer tumor suppressor BRCA2 promotes the specific targeting of RAD51 to single-stranded DNA.</a> Nat. Struct. Mol. Biol. 17, 1263-1265 (2010).</li><li>Genois, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+between+BRCA2+and+RAD51+for+promoting+homologous+recombination+in+Leishmania+infantum.">Interactions between BRCA2 and RAD51 for promoting homologous recombination in Leishmania infantum.</a> Nucleic Acids Res. 40, 6570-6584 (2012).</li><li>Shrestha, B., Smee, C., Gileadi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Baculovirus+expression+vector+system:+an+emerging+host+for+high-throughput+eukaryotic+protein+expression.">Baculovirus expression vector system: an emerging host for high-throughput eukaryotic protein expression.</a> Methods Mol. Biol. 439, 269-289 (2008).</li></ol>

Burada sunulan GST-His rekombinant proteinlerin saflaştırma protokolü boyutları geniş bir aralığının saflaştırılması için uygundur: başarıyla Li Rad51 (41kDa), piBRCA2 (120kDa), PALB2 (130kDa) ve dengesiz yüksek molekül ağırlıklı protein saflaştırılmış Leishmania infantum: Li BRCA2 (125kDa) 6,9. Ayrıca, bu protokol ile saflaştırılmış proteinler 6 biyokimyasal aktif edildi. Bu yöntemin başarısı, sadece arzu edilen protein ekspresyon, çözünür...

Rekombinant proteinlerin saflaştırılması biyokimya temel soruları için önemlidir. Iyon değişim kromatografisi ve boyut dışlama kromatografisi gibi protein saflaştırma geleneksel yollar olduğu, örneğin izoelektrik noktası ve ücret ya da boyutu gibi hedef proteinin fiziksel özelliklerine dayanır. Bu ikinci protein özellikleri önemli ölçüde geleneksel protein saflaştırma stratejilerinde kirletici proteinleri şansını arttırır proteinlerin çeşitli tarafından paylaşılır. Bu sorun, zaman alıcı, birden çok arıtma sütun kullanımı ile engellenebilecektir. Aynı zamanda, ikinci kromatografi yöntemler pahalı deney düzeneği gerektirir. Olguların çoğunda etiket ilgi protein benzersiz olacak gibi afinite etiketi arıtma güçlü, hedef-özgüllük artar. Son zamanlarda yapılan araştırmalarda, Flag-ya da HA-afinite saflaştırma yaygın olarak kullanılmaktadır. Mevcut rec aksineTek etiketleri kullanıldığı ombinant protein saflaştırma protokolleri, iki etiketlerin benzersiz bir bileşimini kurulmuştur. Önerilen yöntem, miktar ve istenen proteinin saflığı arasında optimum bir oranı için, ilgi konusu proteinin C-terminalinde N-terminalinde bir His-tag, bir GST-füzyon etiketinin içerir. GST glutatiyon Sefaroz taneleri üzerinde saflaştırma için yüksek verimli bir uzun etiketi (29 kDa) &#39;dir. Ayrıca, KDV kullanarak bizim yöntem 1 maliyet etkinliğini garanti. (Sadece iki amino asit ilavesi ile sonuçlanan tanıma sekansı LeuGluValLeuPheGln / GlyPro ile) PreScisson enzimi ile GST kapalı yarmak için bir olasılık, bir çok avantajı vardır, örneğin, bu strateji allosterik bir engel nedeniyle fizyolojik protein fonksiyonlarının değişiklikler önler. Diğer protein ucuna kaynaşmış His-tag, küçük bölünmüş GST yıkandıktan, hem de bozulmuş proteinlerin ve diğer protein saflığını daha da arttırmak için ikinci bir arıtma adımında karşılık vermektedir<html> kirleticiler. His-saflaştırma adımı kolonu (TALON reçinesi) için GST geçiş Ek olarak, iletişim kuralı, bir diyaliz adımı gerektirmez. Bu tür saflaştırma işlemlerinde yaygın kirletici maddeler ısı şok proteinlerinin (HSP) &#39;dir. MgCI2 ve ATP ile bir kuluçkalama adımının eklenmesi bu kirleticilerin çıkarılması (Şekil 1) sağlar. Hızlı protein sıvı kromatografi (FPLC) ve Yüksek Performanslı Sıvı Kromatografisi (HPLC), ilgi konusu saflaştırılmış proteinin yüksek verim elde etmek için pahalı enstrümantasyon bağlıdır sıradan yöntemlerdir. Burada mevcut toplu arıtma protokolü, aksine, manuel ve pahalı bir enstrümantal kurulum gerektirmez. Protein yüksek verim protokolünü ölçeklendirme ulaşılabilir. Aynı zamanda, toplu arıtma protokolü ile, elüsyon hacmi FPLC ve HPLC ile verilmezse protein konsantrasyonu arttırmak için ayarlanabilir. ntent &quot;&gt; Aynı zamanda, toplu GST-His arıtma protokolü ile, ~ 10-300 kDa bir boyut aralığı ile proteinler saflaştırılabilir. en büyük avantajlarından biri, aynı anda birkaç proteinleri saflaştırmak gerçeği ile verilir Örneğin, bir vahşi tip ve mutant protein hem de. sunulan protokol başarı sadece, ilgi konusu proteinin ekspresyon seviyesi ve çözünürlüğüne bağlıdır.

<table border="1">
	<tbody>
		<tr>
			<td>Name of the reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
			<td>Comments (optional)</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>REAGENTS</td>
		</tr>
		<tr>
			<td>E.Coli DH10Bac (competent)</td>
			<td>Invitrogen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bac-to-Bac Baculovirus Expression System</td>
			<td>Invitrogen</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Maxi Prep Kit</td>
			<td>Qiagen</td>
			<td>12163</td>
			<td>Solution I and II</td>
		</tr>
		<tr>
			<td>Ultra Pure Bluo-Gal</td>
			<td>Gibco (Life)</td>
			<td>15519028</td>
			<td></td>
		</tr>
		<tr>
			<td>IPTG</td>
			<td>Gibco (Life)</td>
			<td>15529019</td>
			<td></td>
		</tr>
		<tr>
			<td>Sf9 infected cells</td>
			<td>ATCC</td>
			<td>CRL-1711</td>
			<td></td>
		</tr>
		<tr>
			<td>PreScission enzyme</td>
			<td>GE Healthcare</td>
			<td>27084301</td>
			<td></td>
		</tr>
		<tr>
			<td>Grace&#39;s infected medium supplemented</td>
			<td>Gibco (Life)</td>
			<td>11605-094</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum characterized</td>
			<td>Hyclone</td>
			<td>SH30396.03</td>
			<td></td>
		</tr>
		<tr>
			<td>P/S (Penicillin-Streptomycin)</td>
			<td>Gibco (Life)</td>
			<td>15070-063</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutathione Sepharose resin</td>
			<td>GE bioscience</td>
			<td>17075605</td>
			<td></td>
		</tr>
		<tr>
			<td>Protease inhibitor cocktail</td>
			<td>Roche</td>
			<td>11873580001</td>
			<td></td>
		</tr>
		<tr>
			<td>Talon resin</td>
			<td>Clontech</td>
			<td>635504</td>
			<td></td>
		</tr>
		<tr>
			<td>Imidazole</td>
			<td>BioShop</td>
			<td>288324</td>
			<td></td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Gibco (Life)</td>
			<td>15710064</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyclonal GST-antibody</td>
			<td>Production in house</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Monoclonal 6X-His-antibody</td>
			<td>Clontech</td>
			<td>631212</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>Dounce homogenizer (tight)</td>
			<td>Wheaton</td>
			<td>357546</td>
			<td></td>
		</tr>
		<tr>
			<td>Sonicator (Fisher dismembrator)</td>
			<td>Fisher</td>
			<td>Model 150</td>
			<td></td>
		</tr>
		<tr>
			<td>Dialysis bag (50 mm)</td>
			<td>Fisher Scientific</td>
			<td>2115217</td>
			<td></td>
		</tr>
	</tbody>
</table>

gst-his purification: a two-step affinity purification protocol yielding full-length purified proteins

In vitro protein biyokimyasal karakterizasyonu için in Enzymology anahtar tahliller, ilgi konusu saflaştırılmış proteinin yüksek konsantrasyonlarını gerektirmektedir. Protein saflaştırma protokolleri etkinlik, basitlik ve maliyet etkinliğini 1. birleştirmek gerekir. Burada, bir N-terminal Glutathione Sepharose Tag (GST) ve her ikisi de 2,3-kaynaşmış, bir C-terminal 10xHis etiketi 4 dayanan rekombinant protein için yeni bir küçük ölçekli bir afinite arıtma sistemi gibi GST-His yöntemi tarif ilgilenilen proteine. İkinci yapı, protein ekspresyonu için Sf9 5 enfekte olmuş hücrelerin enfeksiyonu için, baculovirüsler oluşturmak için kullanılır. KDV arıtma verimliliği sağlamak için hizmet veren, oldukça uzun bir etiket (29 kDa) &#39;dir. Bununla birlikte, proteinin fizyolojik özelliklerini etkileyebilir. Bu nedenle, bu daha sonra 6 PreScisson enzim kullanılarak protein kesilir. , En fazla saflık sağlamak ve bölünmüş GST çıkarmak için, biznispeten küçük bir His-Tag göre ikinci bir afinite saflaştırma adımı ilave edildi. Önemli olarak, bizim teknik bu nedenle, bozulmuş proteinlerin çıkması ve etkili bir araçtır, proteinin, iki ucunu yan iki farklı etiketler dayanan, tam uzunluklu proteinlerin zenginleştirir. Burada sunulan yöntem, FPLC gibi pahalı bir enstrümantal kurulum, gerektirmez. Ayrıca, ısı şoku proteini kirleri ve nükleik asitler kontamine kaldırmaya nukleaz tedavisi kaldırmak için MgCl2 ve ATP yıkar dahil. Özet olarak, yandan kuşatan iki farklı etiketler kombinasyonu N-ve C-terminal ve etiketler biri kapalı parçalama yeteneği, ilgi konusu bir yüksek derecede arıtılmış ve tam-boy proteinin kurtarma garanti eder.

GST-His saflaştırma protokolü etkinliğini göstermek amacıyla, Rec14, bir S. arıtıldı 32.9 kDa protein pombe. Rec14 cDNA, sırasıyla N-ve C-termini, (Şekil 1A) GST-ve His-etiketi ekleme olanak veren bir modifiye pFastBac1 vektörü içinde klonlandı. Rekombinant bakulovirüs hazırlanabilir ve protein ifadesi için SF9 enfekte hücreleri enfekte etmek için kullanıldı. Çözünür hücre lizatları GST taneleri ile kuluçkalandı ve bağlanmış proteinleri PreScisson prot...

Watch this Scientific Journal Video about GST-His purification: A Two-step Affinity Purification Protocol Yielding Full-length Purified Proteins at JoVE.com

GST-His purification: A Two-step Affinity Purification Protocol Yielding Full-length Purified Proteins

Bu protokol, eşsiz bir şekilde bölünebilir GST-tag ve küçük bir His-tag birleştirilmesiyle yeniden birleştirici proteinlerin saflaştırılmasını sağlayan bir yüksek verimli ve düşük maliyetli, küçük ölçekli protein saflaştırma yöntemi göstermektedir.

GST-His saflaştırma: Tam boy Saflaştırılmış Proteinler Verim iki aşamalı bir saflaştırma protokolü Affinity

Key assays in enzymology for the biochemical characterization of proteins in vitro necessitate high concentrations of the purified protein of interest. ...

gst-his-purification-two-step-affinity-purification-protocol-yielding

Research

JoVE Journal

Biology

41.3K Görüntüleme.  Hôtel-Dieu de Québec.  Bu protokol, eşsiz bir şekilde bölünebilir GST-tag ve küçük bir His-tag birleştirilmesiyle yeniden birleştirici proteinlerin saflaştırılmasını sağlayan bir yüksek verimli ve düşük maliyetli, küçük ölçekli protein saflaştırma yöntemi göstermektedir. 

Video: GST-His purification: A Two-step Affinity Purification Protocol Yielding Full-length Purified Proteins

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

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.

Hsp104 saflaştırılması, 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 ...

Chromatographic Purification of Highly Active Yeast Ribosomes

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers. Particularly troublesome is the fact that lysis of cells releases a large number of proteases and nucleases which can degrade ribosomes. Thus, it is important to separate ribosomes from these enzymes as quickly as possible. Unfortunately, conventional differential ultracentrifugation methods leaves ribosomes exposed to these enzymes for unacceptably long periods of time, impacting their structural integrity and functionality. To address this problem, we utilize a chromatographic method using a cysteine charged Sulfolink resin. This simple and rapid application significantly reduces co-purifying proteolytic and nucleolytic activities, producing high yields of intact, highly biochemically active yeast ribosomes. We suggest that this method should also be applicable to mammalian ribosomes. The simplicity of the method, and the enhanced purity and activity of chromatographically purified ribosome represents a significant technical advancement for the study of eukaryotic ribosomes.

Contamination of preparations of eukaryotic ribosomes purified by traditional methods by co-purifying nucleases and proteases negatively impacts on downstream biochemical and structural analyses. A rapid and simple chromatographic purification method is used to solve this problem using yeast ribosomes as a model system.

Yüksek Aktif Maya Ribozomlar Kromatografik Arıtma

Eukaryotic ribosomes are much more labile as compared to their eubacterial and archael counterparts, thus posing a significant challenge to researchers.  ...

Orthogonal Protein Purification Facilitated by a Small Bispecific Affinity Tag

Due to the high costs associated with purification of recombinant proteins the protocols need to be rationalized. For high-throughput efforts there is a demand for general methods that do not require target protein specific optimization1 . To achieve this, purification tags that genetically can be fused to the gene of interest are commonly used2 . The most widely used affinity handle is the hexa-histidine tag, which is suitable for purification under both native and denaturing conditions3 . The metabolic burden for producing the tag is low, but it does not provide as high specificity as competing affinity chromatography based strategies1,2.
Here, a bispecific purification tag with two different binding sites on a 46 amino acid, small protein domain has been developed. The albumin-binding domain is derived from Streptococcal protein G and has a strong inherent affinity to human serum albumin (HSA). Eleven surface-exposed amino acids, not involved in albumin-binding4 , were genetically randomized to produce a combinatorial library. The protein library with the novel randomly arranged binding surface (Figure 1) was expressed on phage particles to facilitate selection of binders by phage display technology. Through several rounds of biopanning against a dimeric Z-domain derived from Staphylococcal protein A5, a small, bispecific molecule with affinity for both HSA and the novel target was identified6 .
The novel protein domain, referred to as ABDz1, was evaluated as a purification tag for a selection of target proteins with different molecular weight, solubility and isoelectric point. Three target proteins were expressed in Escherishia coli with the novel tag fused to their N-termini and thereafter affinity purified. Initial purification on either a column with immobilized HSA or Z-domain resulted in relatively pure products. Two-step affinity purification with the bispecific tag resulted in substantial improvement of protein purity. Chromatographic media with the Z-domain immobilized, for example MabSelect SuRe, are readily available for purification of antibodies and HSA can easily be chemically coupled to media to provide the second matrix.
This method is especially advantageous when there is a high demand on purity of the recovered target protein. The bifunctionality of the tag allows two different chromatographic steps to be used while the metabolic burden on the expression host is limited due to the small size of the tag. It provides a competitive alternative to so called combinatorial tagging where multiple tags are used in combination1,7.

A novel and highly efficient two-step affinity chromatography protocol has been developed and is described in detail. The method is based on a small purification tag with two inherent affinities and is applicable to a wide range of target proteins with different properties.

Küçük Bispecific Affinity Tag Kolaylaştırılmış Ortogonal Protein Saflaştırma

Due to the high costs associated with purification of recombinant proteins the protocols need to be rationalized. For high-throughput efforts there is a ...

Identification of Protein Interacting Partners Using Tandem Affinity Purification

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein partners. There are many approaches that allow the identification of interacting partners, including the yeast two hybrid system, as well as pull down assays using recombinant proteins and immunoprecipitation of endogenous proteins followed by mass spectrometry identification1. Recent studies have highlighted the utility of double-affinity tag mediated purification, coupled with two specific elution steps in the identification of interacting proteins. This approach, termed Tandem Affinity Purification (TAP), was initially used in yeast2,3 but more recently has been adapted to use in mammalian cells4-8.
As proof-of-concept we have established a tandem affinity purification (TAP) method using the well-characterized eukaryotic translation initiation factor eIF4E9,10.The cellular translation factor eIF4E is a critical component of the cellular eIF4F complex involved in cap-dependent translation initiation10. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence. The TAP tag used in the current study is composed of two Protein G units and a streptavidin binding peptide separated by a Tobacco Etch Virus (TEV) protease cleavage sequence8. To forgo the need for the generation of clonal cell lines, we developed a rapid system that relies on the expression of the TAP-tagged bait protein from an episomally maintained plasmid based on pMEP4 (Invitrogen). Expression of tagged murine eIF4E from this plasmid was controlled using the cadmium chloride inducible metallothionein promoter.
Lysis of the expressing cells and subsequent affinity purification via binding to rabbit IgG agarose, TEV protease cleavage, binding to streptavidin linked agarose and subsequent biotin elution identified numerous proteins apparently specific to the eIF4E pull-down (when compared to control cell lines expressing the TAP tag alone). The identities of the proteins were obtained by excision of the bands from 1D SDS-PAGE and subsequent tandem mass spectrometry. The identified components included the known eIF4E binding proteins eIF4G and 4EBP-1. In addition, other components of the eIF4F complex, of which eIF4E is a component were identified, namely eIF4A and Poly-A binding protein. The ability to identify not only known direct binding partners as well as secondary interacting proteins, further highlights the utility of this approach in the characterization of proteins of unknown function.

Tandem affinity purification is a robust approach for the identification of protein binding partners. As proof of concept, this methodology was applied to the well-characterized translation initiation factor eIF4E to co-precipitate the host cell factors involved in translation initiation. This method is easily adapted to any cellular or viral protein.

Tandem Affinity Arıtma kullanarak Protein etkileşim Ortaklar belirlenmesi

A critical and often limiting step in understanding the function of host and viral proteins is the identification of interacting cellular or viral protein ...

Identification of Protein Complexes in Escherichia coli using Sequential Peptide Affinity Purification in Combination with Tandem Mass Spectrometry

Since most cellular processes are mediated by macromolecular assemblies, the systematic identification of protein-protein interactions (PPI) and the identification of the subunit composition of multi-protein complexes can provide insight into gene function and enhance understanding of biological systems1, 2. Physical interactions can be mapped with high confidence vialarge-scale isolation and characterization of endogenous protein complexes under near-physiological conditions based on affinity purification of chromosomally-tagged proteins in combination with mass spectrometry (APMS). This approach has been successfully applied in evolutionarily diverse organisms, including yeast, flies, worms, mammalian cells, and bacteria1-6. In particular, we have generated a carboxy-terminal Sequential Peptide Affinity (SPA) dual tagging system for affinity-purifying native protein complexes from cultured gram-negative Escherichia coli, using genetically-tractable host laboratory strains that are well-suited for genome-wide investigations of the fundamental biology and conserved processes of prokaryotes1, 2, 7. Our SPA-tagging system is analogous to the tandem affinity purification method developed originally for yeast8, 9, and consists of a calmodulin binding peptide (CBP) followed by the cleavage site for the highly specific tobacco etch virus (TEV) protease and three copies of the FLAG epitope (3X FLAG), allowing for two consecutive rounds of affinity enrichment. After cassette amplification, sequence-specific linear PCR products encoding the SPA-tag and a selectable marker are integrated and expressed in frame as carboxy-terminal fusions in a DY330 background that is induced to transiently express a highly efficient heterologous bacteriophage lambda recombination system10. Subsequent dual-step purification using calmodulin and anti-FLAG affinity beads enables the highly selective and efficient recovery of even low abundance protein complexes from large-scale cultures. Tandem mass spectrometry is then used to identify the stably co-purifying proteins with high sensitivity (low nanogram detection limits).
Here, we describe detailed step-by-step procedures we commonly use for systematic protein tagging, purification and mass spectrometry-based analysis of soluble protein complexes from E. coli, which can be scaled up and potentially tailored to other bacterial species, including certain opportunistic pathogens that are amenable to recombineering. The resulting physical interactions can often reveal interesting unexpected components and connections suggesting novel mechanistic links. Integration of the PPI data with alternate molecular association data such as genetic (gene-gene) interactions and genomic-context (GC) predictions can facilitate elucidation of the global molecular organization of multi-protein complexes within biological pathways. The networks generated for E. coli can be used to gain insight into the functional architecture of orthologous gene products in other microbes for which functional annotations are currently lacking.

Identification of Protein Complexes in Escherichia coli using Sequential Peptide Affinity Purification in Combination with Tandem Mass Spectrometry

Affinity purification of tagged proteins in combination with mass spectrometry (APMS) is a powerful method for the systematic mapping of protein interaction networks and for investigating the mechanistic basis of biological processes. Here, we describe an optimized sequential peptide affinity (SPA) APMS procedure developed for the bacterium Escherichia coli that can be used to isolate and characterize stable multi-protein complexes to near homogeneity even starting from low copy numbers per cell.

Protein Kompleksi belirlenmesi<em&gt; Escherichia coli</em&gt; Tandem Kütle Spektrometresi ile Kombine Sıralı Peptid Affinity Arıtma kullanarak

Since most cellular processes are mediated by macromolecular assemblies, the systematic identification of protein-protein interactions (PPI) and the ...

High-throughput Purification of Affinity-tagged Recombinant Proteins

X-ray crystallography is the method of choice for obtaining a detailed view of the structure of proteins. Such studies need to be complemented by further biochemical analyses to obtain detailed insights into structure/function relationships. Advances in oligonucleotide- and gene synthesis technology make large-scale mutagenesis strategies increasingly feasible, including the substitution of target residues by all 19 other amino acids. Gain- or loss-of-function phenotypes then allow systematic conclusions to be drawn, such as the contribution of particular residues to catalytic activity, protein stability and/or protein-protein interaction specificity.
In order to attribute the different phenotypes to the nature of the mutation - rather than to fluctuating experimental conditions - it is vital to purify and analyse the proteins in a controlled and reproducible manner. High-throughput strategies and the automation of manual protocols on robotic liquid-handling platforms have created opportunities to perform such complex molecular biological procedures with little human intervention and minimal error rates1-5.
Here, we present a general method for the purification of His-tagged recombinant proteins in a high-throughput manner. In a recent study, we applied this method to a detailed structure-function investigation of TFIIB, a component of the basal transcription machinery. TFIIB is indispensable for promoter-directed transcription in vitro and is essential for the recruitment of RNA polymerase into a preinitiation complex6-8. TFIIB contains a flexible linker domain that penetrates the active site cleft of RNA polymerase9-11. This linker domain confers two biochemically quantifiable activities on TFIIB, namely (i) the stimulation of the catalytic activity during the 'abortive' stage of transcript initiation, and (ii) an additional contribution to the specific recruitment of RNA polymerase into the preinitiation complex4,5,12 . We exploited the high-throughput purification method to generate single, double and triple substitution and deletions mutations within the TFIIB linker and to subsequently analyse them in functional assays for their stimulation effect on the catalytic activity of RNA polymerase4. Altogether, we generated, purified and analysed 381 mutants - a task which would have been time-consuming and laborious to perform manually. We produced and assayed the proteins in multiplicates which allowed us to appreciate any experimental variations and gave us a clear idea of the reproducibility of our results.
This method serves as a generic protocol for the purification of His-tagged proteins and has been successfully used to purify other recombinant proteins. It is currently optimised for the purification of 24 proteins but can be adapted to purify up to 96 proteins.

We describe a method for the affinity-tagged purification of recombinant proteins using liquid-handling robotics. This method is generally applicable to the small-scale purification of soluble His-tagged proteins in a high-throughput format.

Affinity etiketli Rekombinant Proteinler Yüksek throughput Arıtma

X-ray crystallography is the method of choice for obtaining a detailed view of the structure of proteins. Such studies need to be complemented by further ...

Purification of Transcripts and Metabolites from Drosophila Heads

For the last decade, we have tried to understand the molecular and cellular mechanisms of neuronal degeneration using Drosophila as a model organism. Although fruit flies provide obvious experimental advantages, research on neurodegenerative diseases has mostly relied on traditional techniques, including genetic interaction, histology, immunofluorescence, and protein biochemistry. These techniques are effective for mechanistic, hypothesis-driven studies, which lead to a detailed understanding of the role of single genes in well-defined biological problems. However, neurodegenerative diseases are highly complex and affect multiple cellular organelles and processes over time. The advent of new technologies and the omics age provides a unique opportunity to understand the global cellular perturbations underlying complex diseases. Flexible model organisms such as Drosophila are ideal for adapting these new technologies because of their strong annotation and high tractability. One challenge with these small animals, though, is the purification of enough informational molecules (DNA, mRNA, protein, metabolites) from highly relevant tissues such as fly brains. Other challenges consist of collecting large numbers of flies for experimental replicates (critical for statistical robustness) and developing consistent procedures for the purification of high-quality biological material. Here, we describe the procedures for collecting thousands of fly heads and the extraction of transcripts and metabolites to understand how global changes in gene expression and metabolism contribute to neurodegenerative diseases. These procedures are easily scalable and can be applied to the study of proteomic and epigenomic contributions to disease.

Purification of Transcripts and Metabolites from Drosophila Heads

We describe here the procedures for the extraction and purification of mRNA and metabolites from Drosophila heads. We are applying these techniques to better understand the cellular perturbations underlying neuronal degeneration. These methodologies can be easily scaled and adapted for other "omic" projects.

Transkript ve Metabolitler gelen saflaştırılması<em&gt; Drosophila</em&gt; Kafaları

For the last decade, we have tried to understand the molecular and cellular mechanisms of neuronal degeneration using Drosophila as a model organism. ...

Protein Purification-free Method of Binding Affinity Determination by Microscale Thermophoresis

Quantitative characterization of protein interactions is essential in practically any field of life sciences, particularly drug discovery. Most of currently available methods of KD determination require access to purified protein of interest, generation of which can be time-consuming and expensive. We have developed a protocol that allows for determination of binding affinity by microscale thermophoresis (MST) without purification of the target protein from cell lysates. The method involves overexpression of the GFP-fused protein and cell lysis in non-denaturing conditions. Application of the method to STAT3-GFP transiently expressed in HEK293 cells allowed to determine for the first time the affinity of the well-studied transcription factor to oligonucleotides with different sequences. The protocol is straightforward and can have a variety of application for studying interactions of proteins with small molecules, peptides, DNA, RNA, and proteins.

Microscale thermophoresis (MST) can be widely used for determination of binding affinity without purification of the target protein from cell lysates. The protocol involves overexpression of the GFP-fused protein, cell lysis in non-denaturing conditions, and detection of MST signal in the presence of varying concentrations of the ligand.

Mikro Termoforosis tarafından Bağlama Affinity belirlenmesi Protein Saflaştırma-ücretsiz Yöntemi

Quantitative characterization of protein  interactions is essential in practically any field of life sciences,  particularly drug discovery. Most of ...

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.

Protein-protein etkileşimi belirlenmesi<em&gt; Drosophila</emTandem Affinity Arıtma tarafından&gt; Adult Başlar (TAP)

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

GST-His saflaştırma: Tam boy Saflaştırılmış Proteinler Verim iki aşamalı bir saflaştırma protokolü Affinity

Özet

Daha Fazla Video Keşfet

Bu videodaki bölümler