我々は法の開発につながる議論アンヌ=マリー·ディオン·コートに感謝します。 JKとRBはFQNRT博士学者、M.-MGはバニエCIHR学者であり、J.-YMはFRSQ上級研究員である。この作品は、自然科学と工学研究評議会からJYへの資金によってサポートされていました。 M.

1。組換えバキュロウイルスの作製バキュロウイルスは、主に、わずかな修正を加えた製造業者のプロトコルに従って、Invitrogen社のBac-to-Bacバキュロウイルス発現系を用いて生成されます。 <ol><li>修正するpFastBac1ベクター（Gibco社、生命）は、GSTおよびHis-タグ（ 図2）を含む作成されました。をpET-52bの（+）ベクター（Novagen）のマルチクローニングサイト（MCS）は、10xHisタグを含有するpFastBac1-ストレプト-10xHisを生成するようにするpFastBac1ベクターのMCSに挿入した。をpET-52bの（+）MCS配列が5 &#39;端および3にHindIII制限部位&#39;端におけるBglII制限部位を付加する、XbaIおよびBlpIを制限部位の間に増幅されたPCRであった。 PCR産物は、次いで、BamHIおよびBglII制限配列の相溶性を使用して、pFastBac1のBamHIおよびHindIIIの制限部位間にクローニングした。目的は、の発現を可能にするpFastBac1を生成することであったのでストレプトアビジンと10xHisタグを用いる組換えタンパク質、ペット-52B（+）のBamHI制限部位がMCSの配列が使用されませんでした。また、XbaI制限部位が既にするpFastBac1のMCSとをpET-52bのMCSに挿入し、これらの（+）内のサイト間で生じる制限部位の重複を避けるために使用されなかった。プレシジョンプロテアーゼ認識部位（LeuGluValLeuPheGln / GlyPro）とのGSTコード配列を、次いで、pFastBac1の - ストレプトマイシン-10xHisに挿入した。をpGEX-6P-2（GEヘルスケア）からGST cDNA配列は、PCR、それぞれ5にNcoIおよびKpnI制限部位を含むプライマー &#39;および3&#39;の末端を増幅した。 NcoI部位は、開始コドンの追加だけでなく、GSTにアラニンを可能にします。 PCR産物を、次いで、ストレプトアビジン-タグの欠失をもたらす、NcoIおよびKpnI制限部位の間にpFastBac1の - ストレプトマイシン-10xHisにクローニングした。このようにして得られた新たな融合ベクターは、pFastBac1の-GST-10xHis命名された。 </li><li> PRをコードするcDNAクローンを作成GST（N末端）およびHisタグ（C末端）の間をpFastBac-GST-10xHisベクターへの関心のotein。 C末端Hisタグとの融合を可能にするためのcDNAの終止コドンを除去するように注意してください。 </li><li> Eを変換（ステップ1.2）で得られた組換えたpFastBacとの大腸菌 DH10Bacコンピバクミドを生成する。コロニーがBluo-galおよびIPTG（10μg/ mlのテトラサイクリン、50μg/ mlのカナマイシン、7μg/ mlのゲンタマイシン、100μg/ mlのBluoを含有選択プレート上で30℃、37℃、数時間で一晩成長させるギャル、40μg/ mlのIPTG）。 </li><li>白の表現型を確認するために、選択プレート上で（ステップ1.3から）2個の白色コロニーを選択し、restreak。 </li><li>ステップ1.4から2白いコロニーをLBの2ミリリットル10μg/ mlのテトラサイクリンを含む、50μg/ mlのカナマイシン、10μg/ mlのゲンタマイシンを接種し、それらを37℃で撹拌（250回転）の下で一晩増殖させ</li><li>バクミドDNAを精製するために、ステップ1.5からの細菌をペレット溶液を300μlの私は細胞を再懸濁し、溶液IIを300μl（キアゲンからマキシプレップキット）を追加します。 、室温で5分間インキュベートし、3MのKOAcのpH 5.5を300μlを加え、氷上で10分間インキュベートする。 4°C、10分間最大速度でサンプルを遠心分離する。上清にイソプロパノールを800μl加え、氷上で10分間インキュベートする。 4℃で15分間サンプルを遠心分離し、70％エタノール500μlでペレットを洗浄する。ペレットを乾燥させトリス-EDTA pH8.0の40μlの滅菌条件下でそれを懸濁します。バクミドDNAは、4℃で保存する必要があります</li><li>製造業者のプロトコルに記載のようにバキュロウイルスを生成する。バキュロウイルスは、光から保護して4℃で保存することができる。 </li></ol> 2。組換えタンパク質発現<ol><li>精製のための最も効率的なバキュロウイルスを選択すると、タンパク質発現のピークに到達する何時監視するために、ミニ感染アッセイaを実行するSは、以下のとおりのSf9の2×10 7に感染バキュロウイルスの133μL（1/150）と（10％FBSおよび1％P / Sで補完）グレースメディアに27℃で培養した細胞を感染させた。 0、24、48で1.5ミリリットルのアリコートを収集し、72時間後に感染。細胞をペレット化し、抗タグ抗体を用いたウエスタンブロッティングにより目的のタンパク質の発現レベルを分析する。 </li><li>ウイルスとメディアの間で1/150の割合で、メディアの500ミリリットル1ml当たり1.0×10 6 Sf9細胞を含むスピナーを感染させるためにステップ2.1から最も効率的なバキュロウイルスを使用してください。感染細胞は27℃で、懸濁液中で増殖し、最大のタンパク質発現（上記ステップ2.1で決定される）に達したときに細胞を回収しましょう​​。ペレット化した細胞は、さらに使用するまで-80℃で保存することができる。 </li></ol> 3。可溶性細胞溶解物の調製以下のインキュベーションステップは全て、軽度の回転下で4℃で行われる。 <ol><li>溶解SGST結合バッファー（150mMのNaCl、1mMのEDTA、0.05％トリトン-X-100、1mMの250mMのNaClの終濃度についてのPBS1XでDTT、およびプロテアーゼ阻害剤の約20 mlの目的タンパク質を発現するF9細胞カクテル（Roche）を氷水浴中で、ダウンスホモジナイザーでソリューション20Xをダウンス、超音波処理3X 30秒ごと（70％出力）し、再び20Xをダウンス。 </li><li> （省略可能）。 1mMのMgCl 2を有する全細胞溶解物をインキュベートし、DNAまたはRNAの混入を除去するために4℃で30分間7ヌクレアーゼ（2.5 U / ml）をベンゾナーゼ。 </li><li> 4℃で30分間18,000 rpmで遠心分離上清を保管してください。 </li><li> （省略可能）。遠心分離機明確な可溶性溶解を得るために4℃、18,000 rpmで30分間、再び上清。目詰まりを回避するために、0.2または0.45μmのフィルターで上澄みを渡します。 </li></ol> 4。 GSTビーズ上のタンパク質の結合<ol><li> GSTビーズを1mlの可溶性細胞溶解物をインキュベートする（で2回予備洗浄GST 10mlを穏やかに回転させながら4℃で1時間、緩衝液）に結合する。 </li></ol> コメント：インキュベーション時間は、タンパク質の安定性及び結合効率に応じて最適化する必要がある。 <ol start="2"><li>クイック700 rpmでスピンし、非結合タンパク質を含む上清を除去し（これは、さらなる分析のために保持することができる）。 GST洗浄緩衝液（350mMのNaClを有する最終的なGST結合緩衝液）を用いてGST-結合タンパク質（ 図3B、レーン1）洗浄する。 </li><li>手順を繰り返し4.2倍。最後の洗浄では、できるだけ多くの上清を除去します。 </li><li>熱ショックタンパク質8の非特異的結合を回避するために、4℃で1時間（10ミリリットルGST結合緩衝液中）、5mMのATPおよび15mMのMgCl 2を有するビーズをインキュベートする。 GST洗浄バッファーでビーズを3回洗浄します。 </li></ol> 5。 GSTのプレシジョン切断<ol><li> GSTビーズを遠心し、上清を除去し、P5のBUFとのGSTビーズを洗浄FER（50mMのpH7.0でのNaHPO 4、500mMのNaCl、10％グリセロール、0.05％トリトン-X-100、5mMイミダゾール）。 </li><li> 4℃で一晩に3時間からP5バッファにプレシジョン酵素で、GST-ビーズをインキュベート（100μLの分画に、GSTビーズを分割し、P5の緩衝液100μlに希釈した酵素の4-8単位（2-4μl）を追加します）。 </li></ol> コメント：プレシジョン工程のインキュベーション時間は、分子量ならびにタンパク質の安定性に応じて最適化する必要がある。分解が観察される場合には、このインキュベーション時間は一晩、2時間の最小値の代わりにまで減少させることができる。 <ol start="3"><li>クイックスピンし、上清を集める。 P5の100μlのを追加した後、この手順を2回繰り返す ビーズにバッファリングし、全ての画分（ 図3B、レーン2）プール。 </li></ol> コメント：残りのビーズは切断効率の分析のために使用することができる（ 図3B </strongの&gt;、レーン3）。通常、タンパク質の70〜80％が切断される。 6。タンパク質結合TALON金属アフィニティー樹脂に<ol><li> 1ミリリットルの3画分に、上からの溶出を分割し、回転下で1時間、100μlのタロン金属アフィニティー樹脂乾燥ビーズ（P5緩衝液で2回予洗）と、それぞれインキュベートする。 </li></ol> コメント：いくつかの画分に溶出を割ると、結合/洗浄の効率を向上させます。 <ol start="2"><li> P30バッファー（30 mMイミダゾールの最終濃度でP5バッファー）で樹脂5分を洗ってください。 </li><li>ステップ6.2倍を繰り返して、単一のチューブ内でビーズをプールする。最後の洗浄の前に、できるだけ多くの上清を除去します。 </li></ol> コメント：これはTALONバインドのサンプル（ 図3B、レーン4）に対応している。 7。精製タンパク質の溶出<ol><li> P5で回転下で5分間蛋白結合するTALON樹脂をインキュベート00緩衝液（500 mMイミダゾールの最終濃度を有するバッファーP5）。バッファ1:1 V / Vのビーズとの比率を使用してください（あなたは乾燥ビーズを200μlを取っていた場合、あなたはP500を200μlを追加する必要があります）。 2回にこの手順を繰り返し、別々にそれぞれの溶出画分を保つ（; 図3B、レーン5-7という名前の溶出1（E1）、溶出2（E2）および溶出3（E3））。 </li></ol> コメント：残りのビーズを溶出効率（ 図3B、レーン8）の分析のために使用することができる。典型的に、タンパク質の60〜80％が合計で溶出する。 <ol start="2"><li>クマシーブルー（ 図3B）、または可視化のためのSYPROタンパク質染色でSDS-PAGEおよび染色の標準BSA濃度で各分画の約20〜40μLをロードすることによって、あなたの精製タンパク質の量と質を分析します。 </li></ol> コメント：目的のタンパク質もthroを検出することが可能抗GSTおよび抗His抗体（ 図3C）を使用して精製操作ughout。 8。精製タンパク質の貯蔵<ol><li> 4℃で、適切な保存緩衝液に対して精製タンパク質（ 例えば、20mMトリス酢酸塩pH8.0で、200mMののKAc、10％グリセロール、1mMのEDTA、0.5mMのDTT）で透析これは、透析中に精製されたタンパク質の沈殿のために確認することが重要です。私たちは通常、攪拌回転下で4℃で1時間、2X透析。 </li><li>精製したタンパク質（10-20μL）の小分けを作り、30分間ドライアイス上で凍結する。 -80℃で一定分量を保存し、多くの融解/凍結サイクルを避ける。 </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>

ここで紹介する、GST-Hisの精製プロトコルは、組換えタンパク質の大きさの広い範囲の精製に適している：我々は成功して李 RAD51（41kDa）、piBRCA2（120kDa）、PALB2（130kDa）、および不安定な高分子量のタンパク質の精製リーシュマニア幼児 ： 李 BRCA2（125kDa）6,9。また、このプロトコルを使用して精製したタンパク質は、6生化学的に活性であった。この方法の...

組換えタンパク質の精製は、生化学の基本的な質問に対処することが重要である。イオン交換クロマトグラフィーおよびサイズ​​排除クロマトグラフィーのようなタンパク質精製の従来の方法は、それぞれ、例えば、その等電点、電荷またはサイズなどの標的タンパク質の物理的性質に依存する。後者のタンパク質特性が大幅に従来のタンパク質精製方法でタンパク質を汚染する可能性を増大させる種々のタンパク質が共有されています。この問題は、時間がかかり、複数の精製カラムの使用により回避することができる。同時に、後者のクロマトグラフィー法は、高価な実験装置を要求する。ほとんどの場合、タグは、目的のタンパク質に固有であるように、アフィニティータグ精製が強く、標的特異性を増加させる。最近の研究では、違反またはHA-アフィニティー精製が広く用いられている。 既存rec視聴とは対照的に単一のタグが使用されるombinantタンパク質精製プロトコルは、2つのタグのユニークな組み合わせを確立した。我々の方法は、所望のタンパク質の量と純度との間の最適な比率のために、目的のタンパク質のC末端にN-末端およびHisタグにおけるGST-タグの融合を含む。 GSTはグルタチオンセファロースビーズでの精製のための非常に効率的で、長いタグ（29 kDa）の、ある。さらに、GSTを使用すると、本手法1の費用対効果を保証します。 （わずか2つのアミノ酸の付加、その結果、認識配列LeuGluValLeuPheGln / GlyProで）プレシジョン酵素GSTを切断する可能性は多くの利点を有し、例えば、この戦略は、アロステリック障害のために、生理学的タンパク質の機能の変化を回避する。他のタンパク質に融合した小端Hisタグは、切断されたGSTを洗い流し、ならびにタンパク質および他の分解によるタンパク質の純度を高めるために第二の精製工程において機能する<html>汚染物質。彼の精製工程カラム（TALON樹脂）にGSTの切り替えとさらに、プロトコルは、透析工程を必要としない。このような精製プロセスにおける一般的な汚染物質は、熱ショックタンパク質（HSP）である。 MgCl 2およびATPとのインキュベーション工程の追加は、これらの汚染物質を除去する（ 図1）を可能にする。 高速タンパク質液体クロマトグラフィー（FPLC）、および高速液体クロマトグラフィー（HPLC）は、関心対象の精製されたタンパク質を高収率で生成するために高価な器具類に依存する一般的な技術である。我々はここで紹介するバッチ精製プロトコールは、対照的に、手動で、高価な楽器のセットアップを必要としません。タンパク質の高収量は、プロトコルをスケールアップして行くことができます。これと同時に、バッチ精製プロトコルで、溶出体積はFPLCまたはHPLCで指定されていないタンパク質濃度を向上させるために調整することができる。 ntent &quot;&gt;また、バッ​​チGST-Hisの精製プロトコルで、〜10〜300 kDaの範囲のサイズを有するタンパク質を精製することができる。最大の利点の一つは、一つは、同時にいくつかのタンパク質を精製することができるという事実によって与えられる。例えば、野生型及びその変異タンパク質の両方が提示されたプロトコルの成功は、単独で目的のタンパク質の発現レベルおよび溶解度に依存する。

<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

インビトロにおけるタンパク質の生化学的特徴付けのための酵素学における重要なアッセイは、関心対象の精製されたタンパク質の高濃度を必要とする。タンパク質精製プロトコルは、効率性、単純性、および費用対効果1を結合する必要があります。ここでは、N-末端グルタチオンセファロースタグ（GST）2,3両融合されるC-末端10xHisタグ4に基づいて、組換えタンパク質のための新たな小規模アフィニティー精製システムとしてGST-Hisの方法を記載目的のタンパク質に。後者の構築物は、タンパク質発現のために5感染したSf9細胞の感染のために、バキュロウイルスを生成するために使用される。 GSTは、浄化効率を確保するのに役立つかなり長いタグ（29 kDa）のである。しかしながら、タンパク質の生理学的特性に影響を与えるかもしれない。従って、それは、その後、プレシジョン酵素6を用いてタンパク質から切断される。最大の純度を保証し、切断されたGSTを除去するために、我々比較的小さいHisタグに基づいて、第二のアフィニティー精製工程を追加した。重要なことには、我々の技術が劣化したタンパク質を除去し、従って、完全長タンパク質を豊かにするための効率的なツールであるタンパク質の両端に隣接する2つの異なるタグに基づいている。ここで紹介する方法は、FPLC等の高価な楽器のセットアップを必要としない。さらに、我々は、夾雑核酸廃止する熱ショックタンパク質不純物およびヌクレアーゼ処理を除去するためにMgCl 2およびATPの洗浄を組み込んだ。要約すると、隣接する2つの異なるタグの組合せN-およびC-末端とタグのいずれかを切断する能力が、興味のある高度に精製された全長タンパク質の回収で評価する。

GST-Hisの精製プロトコールの効率を例証するために、我々はRec14、S.精製 32.9 kDaでpombeのタンパク質。 Rec14 cDNAは、N-およびC-末端GST-およびHis-タグの付加を可能にする我々の修飾するpFastBac1ベクターであった（ 図1A）にクローニングした。組換えバキュロウイルスを調製し、次いで、タンパク質発現のためにSF9に感染した細胞に感染させた。可溶性細胞溶解物をGSTビー?...

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

本プロトコルでは、一意に切断可能なGST-タグおよび小Hisタグを組み合わせることにより組換えタンパク質の精製を可能にする非常に効率的で費用対効果の高い小規模タンパク質精製方法を実証する。

GST-Hisの精製：全長精製タンパク質を降伏二段階アフィニティー精製プロトコル

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

41.1K ビュー.  Hôtel-Dieu de Québec. 本プロトコルでは、一意に切断可能なGST-タグおよび小Hisタグを組み合わせることにより組換えタンパク質の精製を可能にする非常に効率的で費用対効果の高い小規模タンパク質精製方法を実証する。 

ビデオ: 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.

クーマシー有機溶媒および酢酸のないG - 250でゲル中のタンパク質の染色

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

生物学

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の精製、タンパク質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.

高活性酵母のリボソームのクロマトグラフィー精製

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.

小型二重特異性アフィニティタグによって容易に直交するタンパク質の精製

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.

タンデムアフィニティー精製を用いたタンパク質相互作用するパートナーの識別

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

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.

アフィニティータグ組換えタンパク質のハイスループット精製

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 ...

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.

マイクロスケール熱泳動によって結合親和性の決定のタンパク質精製·フリー法

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

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.

組換えタンパク質ベイトを用いてファージディスプレイおよび親和性選択のためのプロトコル

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.

中のタンパク質 - タンパク質相互作用を特定する<em&gt;ショウジョウバエ</emタンデムアフィニティー精製（TAP）による&gt;アダルトヘッド

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

Protein Purification Technique that Allows Detection of Sumoylation and Ubiquitination of Budding Yeast Kinetochore Proteins Ndc10 and Ndc80

Post-translational Modifications (PTMs), such as phosphorylation, methylation, acetylation, ubiquitination, and sumoylation, regulate the cellular function of many proteins. PTMs of kinetochore proteins that associate with centromeric DNA mediate faithful chromosome segregation to maintain genome stability. Biochemical approaches such as mass spectrometry and western blot analysis are most commonly used for identification of PTMs. Here, a protein purification method is described that allows the detection of both sumoylation and ubiquitination of the kinetochore proteins, Ndc10 and Ndc80, in Saccharomyces cerevisiae. A strain that expresses polyhistidine-Flag-tagged Smt3 (HF-Smt3) and Myc-tagged Ndc10 or Ndc80 was constructed and used for our studies. For detection of sumoylation, we devised a protocol to affinity purify His-tagged sumoylated proteins by using nickel beads and used western blot analysis with anti-Myc antibody to detect sumoylated Ndc10 and Ndc80. For detection of ubiquitination, we devised a protocol for immunoprecipitation of Myc-tagged proteins and used western blot analysis with anti-Ub antibody to show that Ndc10 and Ndc80 are ubiquitinated. Our results show that epitope tagged-protein of interest in the His-Flag tagged Smt3 strain facilitates the detection of multiple PTMs. Future studies should allow exploitation of this technique to identify and characterize protein interactions that are dependent on a specific PTM.

This manuscript describes the detection of sumoylation and ubiquitination of kinetochore proteins, Ndc10 and Ndc80, in the budding yeast Saccharomyces cerevisiae.