Bu çalışma Kanada Doğa Bilimleri ve Mühendisliği Araştırma Konseyi, Fonds de Recherche du Quebec Nature et Technologie, Kanada İnovasyon Vakfı ve McGill Üniversitesi başlangıç fonları tarafından desteklendi.

<ol>
	<li>Karplus, M., McCammon, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+dynamics+simulations+of+biomolecules.">Molecular dynamics simulations of biomolecules.</a> Nature Structural &amp; Molecular Biology. 9 (9), 646-652 (2002).</li><li>Campbell, E., 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+role+of+protein+dynamics+in+the+evolution+of+new+enzyme+function.">The role of protein dynamics in the evolution of new enzyme function.</a> Nature Chemical Biology. 12 (11), 944-950 (2016).</li><li>Tokuriki, N., Tawfik, D. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen-exchange+mass+spectrometry+for+the+study+of+intrinsic+disorder+in+proteins.">Hydrogen-exchange mass spectrometry for the study of intrinsic disorder in proteins.</a> Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics. 1834 (6), 1202-1209 (2013).</li><li>Goswami, D., 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=Time+window+expansion+for+HDX+analysis+of+an+intrinsically+disordered+protein.">Time window expansion for HDX analysis of an intrinsically disordered protein.</a> Journal of the American Society for Mass Spectrometry. 24 (10), 1584-1592 (2013).</li><li>Keppel, T. R., Howard, B. A., Weis, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+Unstructured+Regions+and+Synergistic+Folding+in+Intrinsically+Disordered+Proteins+with+Amide+H/D+Exchange+Mass+Spectrometry.">Mapping Unstructured Regions and Synergistic Folding in Intrinsically Disordered Proteins with Amide H/D Exchange Mass Spectrometry.</a> Biochemistry. 50 (40), 8722-8732 (2011).</li><li>Mitchell, J. L., 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=Functional+Characterization+and+Conformational+Analysis+of+the+Herpesvirus+saimiri+Tip-C484+Protein.">Functional Characterization and Conformational Analysis of the Herpesvirus saimiri Tip-C484 Protein.</a> Journal of Molecular Biology. 366 (4), 1282-1293 (2007).</li><li>Pan, J., Han, J., Borchers, C. H., Konermann, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen/deuterium+exchange+mass+spectrometry+with+top-down+electron+capture+dissociation+for+characterizing+structural+transitions+of+a+17+kDa+protein.">Hydrogen/deuterium exchange mass spectrometry with top-down electron capture dissociation for characterizing structural transitions of a 17 kDa protein.</a> Journal of the American Chemical Society. 131 (35), 12801-12808 (2009).</li><li>Habibi, Y., Uggowitzer, K. A., Issak, H., Thibodeaux, C. 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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=Effective+application+of+bicelles+for+conformational+analysis+of+G+protein-coupled+receptors+by+hydrogen/deuterium+exchange+mass+spectrometry.">Effective application of bicelles for conformational analysis of G protein-coupled receptors by hydrogen/deuterium exchange mass spectrometry.</a> Journal of the American Society for Mass Spectrometry. 26 (5), 808-817 (2015).</li><li>Canul-Tec, J. C., 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=Structure+and+allosteric+inhibition+of+excitatory+amino+acid+transporter+1.">Structure and allosteric inhibition of excitatory amino acid transporter 1.</a> Nature. 544 (7651), 446-451 (2017).</li><li>Reading, E., 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=Interrogating+Membrane+Protein+Conformational+Dynamics+within+Native+Lipid+Compositions.">Interrogating Membrane Protein Conformational Dynamics within Native Lipid Compositions.</a> Angewandte Chemie International Edition. 56 (49), 15654-15657 (2017).</li><li>Hentze, N., Mayer, M. 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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent+isotope+effects+on+enzyme+systems.">Solvent isotope effects on enzyme systems.</a> Methods in Enzymology. 87, 551-606 (1982).</li><li>Lau, A. M. C., Ahdash, Z., Martens, C., Politis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deuteros:+software+for+rapid+analysis+and+visualization+of+data+from+differential+hydrogen+deuterium+exchange-mass+spectrometry.">Deuteros: software for rapid analysis and visualization of data from differential hydrogen deuterium exchange-mass spectrometry.</a> Bioinformatics. 35 (7), 3171-3173 (2019).</li><li>Houde, D., Berkowitz, S. A., Engen, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+utility+of+hydrogen/deuterium+exchange+mass+spectrometry+in+biopharmaceutical+comparability+studies.">The utility of hydrogen/deuterium exchange mass spectrometry in biopharmaceutical comparability studies.</a> Journal of Pharmaceutical Sciences. 100 (6), 2071 (2011).</li><li>Burkitt, W., O'Connor, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+the+repeatability+and+reproducibility+of+hydrogen/deuterium+exchange+mass+spectrometry+measurements.">Assessment of the repeatability and reproducibility of hydrogen/deuterium exchange mass spectrometry measurements.</a> Rapid Communications in Mass Spectrometry. 22 (23), 3893-3901 (2008).</li><li>Rob, T., Gill, P. K., Golemi-Kotra, D., Wilson, D. 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Açıklayacak bir şeyimiz yok.

Bu protokolde sunulan HDX-MS iş akışı, proteinlerdeki yapısal dinamik elemanların mekansal dağılımını haritalamak ve bu dinamiklerin pertürbasyona (ligand bağlama, enzim mutagenezi vb.) yanıt olarak nasıl değiştiğini araştırmak için son derece sağlam bir platform sağlar. HDX-MS, konformasyonsal dinamikleri araştırmak için yaygın olarak kullanılan diğer yapısal biyoloji yaklaşımlarına göre birkaç farklı avantaja sahiptir. En önemlisi, sadece az miktarda proteine ihtiyaç vardır. Burad...

Proteinler, femtosaniye ölçeğindeki bağ titreşiminden, birçok saniye içinde meydana gelebilecek tüm protein etki alanlarının yeniden düzenlenmesine kadar zaman ölçeklerinde farklı konformasyonları örnekleyen yapısal olarak dinamik moleküllerdir1. Bu konformasyonsal dalgalanmalar genellikle enzim/protein fonksiyonunun kritik yönleridir. Örneğin, ligand bağlamanın neden olduğu konformasyonel değişiklikler, kataliz için gerekli aktif saha kalıntılarını düzenleyerek, sıralı kinetik mekanizmalarda substrat bağlama bölgelerini tanımlayarak, reaktif ara maddeleri ortamdan koruyarak veya allosterik ağlar aracılığıyla enzim fonksiyonunu modüle ederek enzim fonksiyonunu modüle etmek için genellikle kritik öneme sahiptir. Son çalışmalar ayrıca, konformasyonel dinamiklerin evrim boyunca korunabileceğini ve korunmuş moleküler hareketlere pertürbasyonların substrat özgüllüğündeki değişiklikler ve yeni enzim fonksiyonlarının ortaya çıkması ile ilişkili olabileceğini göstermiştir2,3.
Son yıllarda, hidrojen-döteryum değişim kütle spektrometresi (HDX-MS), protein konformasyonel manzaraların ligand bağlama veya mutajensis 4 ,5,6,7gibi pertürbasyonlara nasıl tepki verdiğini araştırmak için güçlü bir teknik olarak hızla ortaya çıkmıştır. Tipik bir HDX-MS deneyinde (Şekil 1), D2O'da hazırlanan tampona bir ilgi proteini yerleştirilir, bu da çözücü değiştirilebilir protonların döter ile değiştirilmesini tetikler. Peptit bağlarının amid moiety'nin değişim oranı, pH'a, yerel amino asit dizisine ve amide8'inyerel yapısal ortamına bağlıdır. Hidrojen yapıştırma etkileşimleri yapan amidler (α-helices ve β yapraklarında bulunanlar gibi) proteinin toplu çözücüye maruz kalan yapılandırılmamış bölgelerindeki ortalardan daha yavaş değiş tokuş eder. Bu nedenle, döteryum alımının kapsamı enzimin yapısının bir yansımasıdır. Konformasyonsal olarak dinamik olan veya ligand bağlanması üzerine yapısal geçişler geçiren enzimlerin ölçülebilir bir HDX yanıtı vermesinin beklenebilir olması beklenir.
Yapılandırılmış bir amidin yavaş döviz kurunun mekanistik temeli Şekil 2 5,8,9'da gösterilmiştir. HDX'e tabi tutulabilmesi için, yapılandırılmış bölgenin öncelikle, hdx değişimini belirli bir asit / baz kimyasal mekanizma ile katalİze eden çözücü moleküllerinin değiştirilebilir amide erişebilmesi için geçici olarak açılmış bir uygunluğu örneklemesi gerekir. Sonuçta, kimyasal döviz kurunun(kkimyası)göreli büyüklükleri ve katlama ve yeniden katlama oranları (kaçık ve kkapanış) deneyde ölçülen HDX oranını belirler5,8. Bu basit kinetik modelden, döteryum alımının kapsamının alttaki konformasyonsal dinamikleri yansıtacağı açıktır (kaçık ve kkapanışıile tanımlandığı gibi). Çoğu HDX-MS deneyi, değişim reaksiyonunu takiben, ilgi proteininin peptitlere sindirildiği ve her peptit tarafından döteryum alımının kütle7'debir artış olarak ölçüldüğü aşağıdan yukarıya bir iş akışında gerçekleştirilir. Bu şekilde, HDX-MS, pertürbasyonların enzim konformasyonel dinamiklerin peptitlerin yerel mekansal ölçeğinde eşlenmesine izin verir ve araştırmacının pertürbasyonun ilgi enziminin farklı bölgelerindeki dinamikleri nasıl değiştirdiğini değerlendirmesini sağlar.
HDX-MS yaklaşımının protein yapısal dinamiklerini aydınlatıcı avantajları çoktur. İlk olarak, yöntem küçük miktarlarda yerli proteinle veya kuaterner yapıya sahip sistemlerde protein kompleksleri üzerindegerçekleştirilebilir 10. Aşağıdan yukarıya HDX-MS iş akışı, ilgi protein dizisini kapsayan yeterli sayıda güvenle tanımlanmış peptit sağladığı sürece, testte kullanılan enzim preparatının yüksek orandasaflaştırılması11,12, için bile gerekli değildir. Ayrıca, HDX-MS, tek moleküllü floresan çalışmalarında kullanılacağı gibi bölgeye özgü protein etiketlemesine gerek kalmadan yakın yerel koşullar altında konformasyonsal dinamikler hakkında bilgi sağlayabilir13ve araştırılabilen protein veya protein kompleksinin boyut sınırı yoktur (nükleer manyetik rezonans [NMR] spektroskopisi gibi yaklaşımları zorlaştırır)7,14. Son olarak, X-ışını kristalografisi 15 , 16,17,18ile incelenmesi zor olan özünde düzensiz proteinleri incelemek için zaman çözümlenmiş HDX-MS yöntemleri kullanılabilir. HDX-MS'in ana sınırlaması, verilerin düşük yapısal çözünürlükte olmasıdır. HDX-MS verileri, konformasyonsal dinamiklerin nerede değiştiğine işaret etmek ve birleştirilmiş konformasyon değişikliklerini ortaya çıkarmak için yararlıdır, ancak genellikle gözlemlenen değişimi yönlendiren hassas moleküler mekanizma hakkında çok fazla bilgi sağlamaz. Elektron yakalama ayrışma yöntemlerinin protein HDX-MS verileriyle kombinasyonundaki son gelişmeler, değişim alanlarının tek amino asit kalıntıları19ile eşlenmesi için umut vaat etmektedir, ancak HDX-MS verileri tarafından iletilen yapısal modellere netlik sağlamak için biyokimyasal ve yapısal çalışmaların takip edilmesi hala sıklıkla gereklidir.
Aşağıda, hdx-ms test geliştirilmesi için ayrıntılı bir protokol20. Aşağıda sunulan numune hazırlama protokolleri genellikle sulu tamponlarda iyi çözünürlük gösteren herhangi bir protein için geçerli olmalıdır. Proteinler için deterjan veya fosfolipidler21, 22, 23, 24varlığında test edilmesi gerekenden daha özel numune hazırlama yöntemleri ve HDX-MS iş akışları mevcuttur. HDX-MS veri toplama için enstrümantal ayarlar, sıvı kromatografi sistemine bağlı olarak yüksek çözünürlüklü dörtlü uçuş süresi kütle spektrometresi için açıklanmıştır. Benzer karmaşıklık ve çözünürlük verileri, piyasada bulunan bir dizi sıvı kromatografi-kütle spektrometresi (LC-MS) sisteminden herhangi birinde toplanabilir. Ticari olarak kullanılabilen bir yazılım paketi kullanılarak veri işlemenin önemli yönleri de sağlanır. Ayrıca, daha geniş HDX-MS topluluğu12tarafından yapılan önerilerle tutarlı veri toplama ve analiz kılavuzları sunuyoruz. Açıklanan protokol, bir antimikrobiyal peptit doğal ürününün multistep olgunlaşmasını katalize eden bir lantiipeptid sentezi olan HalM2'nin dinamik yapısal özelliklerini incelemek için kullanılır20. HDX-MS'in alt tabaka bağlama sitelerini ve önceki karakterizasyondan kaçan allosterik özellikleri ortaya çıkarmak için nasıl kullanılabileceğini gösteriyoruz. Protein HDX-MS ile ilgili diğer birkaç protokol son yıllarda yayınlanmıştır25,26. Mevcut çalışma ile birlikte, bu önceki katkılar okuyucuya deneysel tasarımda biraz esneklik sağlamalıdır.

<table>
	<tbody>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>[glu-1]-fibrinopeptide B (Glu-Fib)</td>
			<td>BioBasic</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr>
			<td>0.5 mL Amicon Ultracel 10k centrifugal filtration device (Millipore)</td>
			<td>Milipore Sigma</td>
			<td>UFC501096</td>
			<td></td>
		</tr>
		<tr>
			<td>acetonitrile</td>
			<td>Fisher</td>
			<td>A955-1</td>
			<td></td>
		</tr>
		<tr>
			<td>AMP-PNP</td>
			<td>SIGMA</td>
			<td>A2647-25MG</td>
			<td></td>
		</tr>
		<tr>
			<td>ATP</td>
			<td>SIGMA</td>
			<td>a2383-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>D2O</td>
			<td>ALDRICH</td>
			<td>435767-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>formic acid</td>
			<td>Thermo Fisher</td>
			<td>28905</td>
			<td></td>
		</tr>
		<tr>
			<td>guanidine-HCl</td>
			<td>VWR</td>
			<td>97063-764</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Fisher</td>
			<td>BP310-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium chloride</td>
			<td>SiGMA-Aldrich</td>
			<td>63068-250G</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>BioBasic</td>
			<td>PB0440</td>
			<td></td>
		</tr>
		<tr>
			<td>potassium phosphate</td>
			<td>BioBasic</td>
			<td>PB0445</td>
			<td></td>
		</tr>
		<tr>
			<td>TCEP Hydrochloride</td>
			<td>TRC Canada</td>
			<td>T012500</td>
			<td>peptide was synthesized upon request</td>
		</tr>
		<tr>
			<td>Name of Material/ Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments/Description</td>
		</tr>
		<tr>
			<td>software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Deuteros</td>
			<td>Andy M C Lau, et al</td>
			<td>version 1.08</td>
			<td></td>
		</tr>
		<tr>
			<td>DynamX</td>
			<td>Waters</td>
			<td>version 3.0</td>
			<td></td>
		</tr>
		<tr>
			<td>MassLynx</td>
			<td>Waters</td>
			<td>version 4.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein Lynx 
			Global Server (PLGS)</td>
			<td>Waters</td>
			<td>version 3.0.3</td>
			<td></td>
		</tr>
		<tr>
			<td>PyMOL</td>
			<td>Schr&#246;dinger</td>
			<td>version 2.2.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Name of Material/ Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments/Description</td>
		</tr>
		<tr>
			<td>Instrument and equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ACQUITY UPLC BEH C18 analytical Column</td>
			<td>Waters</td>
			<td>186002346</td>
			<td></td>
		</tr>
		<tr>
			<td>ACQUITY UPLC BEH C8 VanGuard Pre-column</td>
			<td>Waters</td>
			<td>186003978</td>
			<td></td>
		</tr>
		<tr>
			<td>ACQUITY UPLC M-Class HDX System</td>
			<td>Waters</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HDX Manager</td>
			<td>Waters</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>microtip pH electrode</td>
			<td>Thermo Fisher</td>
			<td>13-620-291</td>
			<td></td>
		</tr>
		<tr>
			<td>Waters Enzymate BEH column or Pepsin solumn</td>
			<td>Waters</td>
			<td>186007233</td>
			<td></td>
		</tr>
		<tr>
			<td>Waters Synapt G2-Si</td>
			<td>Waters</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a hydrogen-deuterium exchange mass spectrometry (hdx-ms) platform for investigating peptide biosynthetic enzymes

Hidrojen-döteryum değişim kütle spektrometresi (HDX-MS), enzim konformasyon değişikliklerinin ve enzim-substrat etkileşimlerinin biyofiziksel karakterizasyonu için güçlü bir yöntemdir. HDX-MS, birçok faydası arasında sadece az miktarda malzeme tüketir, enzim/substrat etiketlemesine gerek kalmadan yakın yerel koşullar altında gerçekleştirilebilir ve büyük enzimler ve multiprotein kompleksleri için bile enzim konformasyonsal dinamikleri−hakkında mekansal olarak çözülmüş bilgiler sağlayabilir. Yöntem, ilgi çekici enzimin D2O'da hazırlanan tampona seyreltilmesiyle başlatılır. Bu, peptit bağı amidlerinde (N-H) protiyumun döteryum (N-D) ile değişimini tetikler. İstenilen değişim zaman noktalarında reaksiyon aliquotları söndürülür, enzim peptitlere proteoliz edilir, peptitler ultra performanslı sıvı kromatografisi (UPLC) ile ayrılır ve her peptitin kütleslerindeki değişim (hidrojenin döteryum ile değişimi nedeniyle) MS tarafından kaydedilir. Her peptit tarafından döteryum alımı miktarı, bu peptitin yerel hidrojen yapıştırma ortamına bağlıdır. Enzim değişim döteryumunun çok dinamik bölgelerinde çok hızlı bir şekilde bulunan peptitler bulunurken, iyi sıralanmış bölgelerden elde edilen peptitler çok daha yavaş bir değişime uğrar. Bu şekilde, HDX oranı lokal enzim konformasyon dinamiklerini rapor eder. Farklı ligandların varlığında döteryum alma seviyelerine pertürbasyonlar daha sonra ligand bağlama alanlarını haritalamak, allosterik ağları tanımlamak ve enzim fonksiyonundaki konformasyonel dinamiklerin rolünü anlamak için kullanılabilir. Burada, lanteptid adı verilen bir tür peptit doğal ürünün biyosentezini daha iyi anlamak için HDX-MS'i nasıl kullandığımızı gösteriyoruz. Lanthipeptides, geleneksel yapısal biyoloji yaklaşımlarıyla incelenmesi zor olan büyük, çok işlevli, konformasyonel dinamik enzimler tarafından çeviri sonrası değiştirilen genetik olarak kodlanmış peptitlerdir. HDX-MS, bu tür enzimlerin mekanistik özelliklerini araştırmak için ideal ve uyarlanabilir bir platform sağlar.

Proteolitik sindirimin kalitesini ve her örnek enjeksiyon kümesi için iş akışının tekrarlanabilirliğini değerlendirmek gerekir. Bu nedenle, HDX-MS tahlillerini yapmadan önce, ilgi çekici proteinin proteolizi, ters faz sıvı kromatografisi ve gaz fazı iyon hareketliliği kullanılarak peptitlerin ayrılması ve MS kullanılarak peptitlerin tespiti için etkili koşulların oluşturulması esastır. Bu amaçla öncelikle ilgi çekici proteine yönelik referans örnekleri (döteryum yokluğunda toplanır) ara?...

Watch this Scientific Journal Video about A Hydrogen-Deuterium Exchange Mass Spectrometry HDX-MS Platform for Investigating Peptide Biosynthetic Enzymes at JoVE.com

A Hydrogen-Deuterium Exchange Mass Spectrometry HDX-MS Platform for Investigating Peptide Biosynthetic Enzymes

Lanthipeptide sentezleri peptit doğal ürünlerin biyosentezi sırasında katalizör multistep reaksiyonları. Burada, lanteptid sentezlerinin konformasyonel dinamiklerini ve peptit doğal ürün biyosentezinde yer alan diğer benzer enzimleri incelemek için bunların kullanılabileceği sürekli, aşağıdan yukarıya, hidrojen-döteryum değişim kütle spektrometresi (HDX-MS) iş akışını açıklıyoruz.

Peptit Biyosintetik Enzimleri Araştırmak için Hidrojen-Döteryum Değişim Kütle Spektrometresi (HDX-MS) Platformu

Hydrogen-deuterium exchange mass spectrometry (HDX-MS) is a powerful method for the biophysical characterization of enzyme conformational changes and ...

a-hydrogen-deuterium-exchange-mass-spectrometry-hdx-ms-platform-for

Research

JoVE Journal

Biochemistry

A Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS) Platform for Investigating Peptide Biosynthetic Enzymes

7.8K Görüntüleme.  McGill University. Lanthipeptide sentezleri peptit doğal ürünlerin biyosentezi sırasında katalizör multistep reaksiyonları. Burada, lanteptid sentezlerinin konformasyonel dinamiklerini ve peptit doğal ürün biyosentezinde yer alan diğer benzer enzimleri incelemek için bunların kullanılabileceği sürekli, aşağıdan yukarıya, hidrojen-döteryum değişim kütle spektrometresi (HDX-MS) iş akışını açıklıyoruz.

Video: A Hydrogen-Deuterium Exchange Mass Spectrometry HDX-MS Platform for Investigating Peptide Biosynthetic Enzymes

Time-resolved ElectroSpray Ionization Hydrogen-deuterium Exchange Mass Spectrometry for Studying Protein Structure and Dynamics

Intrinsically disordered proteins (IDPs) have long been a challenge to structural biologists due to their lack of stable secondary structure elements. Hydrogen-Deuterium Exchange (HDX) measured at rapid time scales is uniquely suited to detect structures and hydrogen bonding networks that are briefly populated, allowing for the characterization of transient conformers in native ensembles. Coupling of HDX to mass spectrometry offers several key advantages, including high sensitivity, low sample consumption and no restriction on protein size. This technique has advanced greatly in the last several decades, including the ability to monitor HDX labeling times on the millisecond time scale. In addition, by incorporating the HDX workflow onto a microfluidic platform housing an acidic protease microreactor, we are able to localize dynamic properties at the peptide level. In this study, Time-Resolved ElectroSpray Ionization Mass Spectrometry (TRESI-MS) coupled to HDX was used to provide a detailed picture of residual structure in the tau protein, as well as the conformational shifts induced upon hyperphosphorylation.

Conformational flexibility plays a critical role in protein function. Herein, we describe the use of time-resolved electrospray ionization mass spectrometry coupled to hydrogen-deuterium exchange for probing the rapid structural changes that drive function in ordered and disordered proteins.

Zaman çözülmesi elektro sprey iyonizasyon Hidrojen-döteryum Değişim Kütle Spektrometre Protein Yapısı ve Dinamikleri incelenmesi için

Intrinsically disordered proteins (IDPs) have long been a challenge to structural biologists due to their lack of stable secondary structure elements. ...

Biyokimya

Resolving Affinity Purified Protein Complexes by Blue Native PAGE and Protein Correlation Profiling

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological processes. Affinity purification coupled to mass spectrometry (AP-MS) has become the method of choice for identifying protein-protein interactions. However, conventional AP-MS studies provide information on protein interactions, but the organizational information is lost. To address this issue, we developed a strategy to unravel the distinct functional assemblies a protein might be involved in, by resolving affinity-purified protein complexes prior to their characterization by mass spectrometry. Protein complexes isolated through affinity purification of a bait protein using an epitope tag and competitive elution are separated through blue native electrophoresis. Comparison of protein migration profiles through correlation profiling using quantitative mass spectrometry allows assignment of interacting proteins to distinct molecular entities. This method is able to resolve protein complexes of close molecular weights that might not be resolved by traditional chromatographic techniques such as gel filtration. With little more work than conventional AP-geLC-MS/MS, we demonstrate this strategy may in many cases be adequate for obtaining protein complex topological information concomitantly to identifying protein interactions.

Here we present protocols for affinity purification of protein complexes and their separation by blue native PAGE, followed by protein correlation profiling using label free quantitative mass spectrometry. This method is useful to resolve interactomes into distinct protein complexes.

Mavi Yerli PAGE ve Protein İlişkisi Profil Yöntemi ile Affinity Saf protein Kompleksler çözümleniyor

Most proteins act in association with others; hence, it is crucial to characterize these functional units in order to fully understand biological ...

Lipid Droplet Isolation for Quantitative Mass Spectrometry Analysis

Lipid droplets are vital to the replication of a variety of different pathogens, most prominently the Hepatitis C Virus (HCV), as the putative site of virion morphogenesis. Quantitative lipid droplet proteome analysis can be used to identify proteins that localize to or are displaced from lipid droplets under conditions such as virus infections. Here, we describe a protocol that has been successfully used to characterize the changes in the lipid droplet proteome following infection with HCV. We use Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) and thus label the complete proteome of one population of cells with &#34;heavy&#34; amino acids to quantitate the proteins by mass spectrometry. For lipid droplet isolation, the two cell populations (i.e.&#160;HCV-infected/&#34;light&#34; amino acids and uninfected control/&#34;heavy&#34; amino acids) are mixed 1:1 and lysed mechanically in hypotonic buffer. After removing the nuclei and cell debris by low speed centrifugation, lipid droplet-associated proteins are enriched by two subsequent ultracentrifugation steps followed by three washing steps in isotonic buffer. The purity of the lipid droplet fractions is analyzed by western blotting with antibodies recognizing different subcellular compartments. Lipid droplet-associated proteins are then separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Coomassie staining. After tryptic digest, the peptides are quantified by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Using this method, we identified proteins recruited to lipid droplets upon HCV infection that might represent pro- or antiviral host factors. Our method can be applied to a variety of different cells and culture conditions, such as infection with pathogens, environmental stress, or drug treatment.

Lipid droplets are important organelles for the replication of several pathogens, including the Hepatitis C Virus (HCV). We describe a method to isolate lipid droplets for quantitative mass spectrometry of associated proteins; it can be used under a variety of conditions, such as virus infection, environmental stress, or drug treatment.

Kantitatif Kütle Spektrometresi Analiz lipid Damlacık izolasyonu

Lipid droplets are vital to the replication of a variety of different pathogens, most prominently the Hepatitis C Virus (HCV), as the putative site of ...

Sample Preparation for Mass Spectrometry-based Identification of RNA-binding Regions

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most cases, the action of noncoding RNAs is mediated by proteins whose functions are in turn regulated by these interactions with noncoding RNAs. Consistent with this, a growing number of proteins involved in nuclear functions have been reported to bind RNA and in a few cases the RNA-binding regions of these proteins have been mapped, often through laborious, candidate-based methods.
Here, we report a detailed protocol to perform a high-throughput, proteome-wide unbiased identification of RNA-binding proteins and their RNA-binding regions. The methodology relies on the incorporation of a photoreactive uridine analog in the cellular RNA, followed by UV-mediated protein-RNA crosslinking, and mass spectrometry analyses to reveal RNA-crosslinked peptides within the proteome. Although we describe the procedure for mouse embryonic stem cells, the protocol should be easily adapted to a variety of cultured cells.

We describe a protocol to identify RNA-binding proteins and map their RNA-binding regions in live cells using UV-mediated photocrosslinking and mass spectrometry.

Kütle spektrometresi tabanlı kimlik RNA-bağlama bölgelerinin için numune hazırlama

Noncoding RNAs play important roles in several nuclear processes, including regulating gene expression, chromatin structure, and DNA repair. In most ...

Optimal Preparation of Formalin Fixed Samples for Peptide Based Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging Workflows

The use of matrix-assisted laser desorption/ionization, mass spectrometry imaging (MALDI MSI) has rapidly expanded, since this technique analyzes a host of biomolecules from drugs and lipids to N-glycans. Although various sample preparation techniques exist, detecting peptides from formaldehyde preserved tissues remains one of the most difficult challenges for this type of mass spectrometric analysis. For this reason, we have created and optimized a robust methodology that preserves the spatial information contained within the sample, while eliciting the greatest number of ionizable peptides. We have also aimed to achieve this in a cost effective and simple way, thereby eliminating potential bias or preparation error, which can occur when using automated instrumentation. The end result is a reproducible and inexpensive protocol.

This protocol describes a reproducible and reliable method for the sublimation-based preparation of formalin fixed tissue destined for imaging mass spectrometry.

Örnekleri için matris peptit esaslı tamir Formalin en iyi hazırlık lazer desorpsiyon/iyonlaşma kütle spektrometresi iş akışlarını görüntüleme destekli

The use of matrix-assisted laser desorption/ionization, mass spectrometry imaging (MALDI MSI) has rapidly expanded, since this technique analyzes a host ...

Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry

Living organisms regularly need to cope with fluctuating environments during their life cycle, including changes in temperature, pH, the accumulation of reactive oxygen species, and more. These fluctuations can lead to a widespread protein unfolding, aggregation, and cell death. Therefore, cells have evolved a dynamic and stress-specific network of molecular chaperones, which maintain a "healthy" proteome during stress conditions. ATP-independent chaperones constitute one major class of molecular chaperones, which serve as first-line defense molecules, protecting against protein aggregation in a stress-dependent manner. One feature these chaperones have in common is their ability to utilize structural plasticity for their stress-specific activation, recognition, and release of the misfolded client. 
In this paper, we focus on the functional and structural analysis of one such intrinsically disordered chaperone, the bacterial redox-regulated Hsp33, which protects proteins against aggregation during oxidative stress. Here, we present a toolbox of diverse techniques for studying redox-regulated chaperone activity, as well as for mapping conformational changes of the chaperone, underlying its activity. Specifically, we describe a workflow which includes the preparation of fully reduced and fully oxidized proteins, followed by an analysis of the chaperone anti-aggregation activity in vitro using light-scattering, focusing on the degree of the anti-aggregation activity and its kinetics. To overcome frequent outliers accumulated during aggregation assays, we describe the usage of Kfits, a novel graphical tool which allows easy processing of kinetic measurements. This tool can be easily applied to other types of kinetic measurements for removing outliers and fitting kinetic parameters. To correlate the function with the protein structure, we describe the setup and workflow of a structural mass spectrometry technique, hydrogen-deuterium exchange mass spectrometry, that allows the mapping of conformational changes on the chaperone and substrate during different stages of Hsp33 activity. The same methodology can be applied to other protein-protein and protein-ligand interactions.

Defining Hsp33&#039;s Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry

One of the most challenging stress conditions that organisms encounter during their lifetime involves the accumulation of oxidants. During oxidative stress, cells heavily rely on molecular chaperones. Here, we present methods used to investigate the redox-regulated anti-aggregation activity, as well as to monitor structural changes governing the chaperone function using HDX-MS.

Hsp33'ın redoks düzenlenir refakatçi etkinlik tanımlama ve Hsp33 konformasyon değişiklikleri hidrojen-döteryum Exchange kütle spektrometresi kullanarak eşleme

Living organisms regularly need to cope with fluctuating environments during their life cycle, including changes in temperature, pH, the accumulation of ...

Detection of Protein Ubiquitination Sites by Peptide Enrichment and Mass Spectrometry

The posttranslational modification of proteins by the small protein ubiquitin is involved in many cellular events. After tryptic digestion of ubiquitinated proteins, peptides with a diglycine remnant conjugated to the epsilon amino group of lysine (&#39;K-&#949;-diglycine&#39; or simply &#39;diGly&#39;) can be used to track back the original modification site. Efficient immunopurification of diGly peptides combined with sensitive detection by mass spectrometry has resulted in a huge increase in the number of ubiquitination sites identified up to date. We have made several improvements to this workflow, including offline high pH reverse-phase fractionation of peptides prior to the enrichment procedure, and the inclusion of more advanced peptide fragmentation settings in the ion routing multipole. Also, more efficient cleanup of the sample using a filter-based plug in order to retain the antibody beads results in a greater specificity for diGly peptides. These improvements result in the routine detection of more than 23,000 diGly peptides from human cervical cancer cells (HeLa) cell lysates upon proteasome inhibition in the cell. We show the efficacy of this strategy for in-depth analysis of the ubiquitinome profiles of several different cell types and of in vivo samples, such as brain tissue. This study presents an original addition to the toolbox for protein ubiquitination analysis to uncover the deep cellular ubiquitinome.

We present a method for the purification, detection, and identification of diGly peptides that originate from ubiquitinated proteins from complex biological samples. The presented method is reproducible, robust, and outperforms published methods with respect to the level of depth of the ubiquitinome analysis.

Peptit Zenginleştirme ve Kütle Spektrometresi ile Protein Ubiquitinasyon Sitelerinin Saptanması

The posttranslational modification of proteins by the small protein ubiquitin is involved in many cellular events. After tryptic digestion of ...

Nitropeptide Profiling and Identification Illustrated by Angiotensin II

Protein nitration is one of the most important post-translational modifications (PTM) on tyrosine residues and it can be induced by chemical actions of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in eukaryotic cells. Precise identification of nitration sites on proteins is crucial for understanding the physiological and pathological processes related to protein nitration, such as inflammation, aging, and cancer. Since the nitrated proteins are of low abundance in cells even under induced conditions, no universal and efficient methods have been developed for the profiling and identification of protein nitration sites. Here we describe a protocol for nitropeptide enrichment by using a chemical reduction reaction and biotin labeling, followed by high resolution mass spectrometry. In our method, nitropeptide derivatives can be identified with high accuracy. Our method exhibits two advantages compared to the previously reported methods. First, dimethyl labeling is used to block the primary amine on nitropeptides, which can be used to generate quantitative results. Second, a disulfide bond containing NHS-biotin reagent is used for the enrichment, which can be further reduced and alkylated to enhance the detection signal on a mass spectrometer. This protocol has been successfully applied to the model peptide Angiotensin II in the current paper.

Proteomic profiling of tyrosine-nitrated proteins has been a challenging technique due to the low abundance of the 3-nitrotyrosine modification. Here we describe a novel approach for nitropeptide enrichment and profiling by using Angiotensin II as the model. This method can be extended for other in vitro or in vivo systems.

Anjiyotensin II tarafından gösterilen nitropeptid profil oluşturma ve tanımlama

Protein nitration is one of the most important post-translational modifications (PTM) on tyrosine residues and it can be induced by chemical actions of ...

A Plasma Sample Preparation for Mass Spectrometry using an Automated Workstation

Sample preparation for mass spectrometry analysis in proteomics requires enzymatic cleavage of proteins into a peptide mixture. This process involves numerous incubation and liquid transfer steps in order to achieve denaturation, reduction, alkylation, and cleavage. Adapting this workflow onto an automated workstation can increase efficiency and reduce coefficients of variance, thereby providing more reliable data for statistical comparisons between sample types. We previously described an automated proteomic sample preparation workflow1. Here, we report the development of a more efficient and better controlled workflow with the following advantages: 1) The number of liquid transfer steps is reduced from nine to six by combining reagents; 2) Pipetting time is reduced by selective tip pipetting using a 96-position pipetting head with multiple channels; 3) Potential throughput is increased by the availability of up to 45 deck positions; 4) Complete enclosure of the system provides improved temperature and environmental control and reduces the potential for contamination of samples or reagents; and 5) The addition of stable isotope labeled peptides, as well as &#946;-galactosidase protein, to each sample makes monitoring and quality control possible throughout the entire process. These hardware and process improvements provide good reproducibility and improve intra-assay and inter-assay precision (CV of less than 20%) for LC-MS based protein and peptide quantification. The entire workflow for digesting 96 samples in a 96-well plate can be completed in approximately 5 hours.

Here, we present an automated plasma protein digestion method for mass spectrometry-based quantitative proteomic analysis. In this protocol, the liquid transferring and incubation steps for protein denaturation, reduction, alkylation, and trypsin digestion reactions are streamlined and automated. It takes approximately five hours to prepare a 96-well plate with desired precision.

Otomatik İş İstasyonu Kullanarak Kütle Spektrometresi Için Plazma Numune Spektrometresi Hazırlığı

Sample preparation for mass spectrometry analysis in proteomics requires enzymatic cleavage of proteins into a peptide mixture. This process involves ...

Sample Preparation for Probe Electrospray Ionization Mass Spectrometry

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ratios (m/z), which are useful to deduce molecular weights and structures. While it is essentially a destructive analytical method, recent advancements in the ambient ionization technique have enabled us to acquire data while leaving tissue in a relatively intact state in terms of integrity. Probe electrospray ionization (PESI) is a so-called direct method because it does not require complex and time-consuming pretreatment of samples. A fine needle serves as a sample picker, as well as an ionization emitter. Based on the very sharp and fine property of the probe tip, destruction of the samples is minimal, allowing us to acquire the real-time molecular information from living things in situ. Herein, we introduce three applications of PESI-MS technique that will be useful for biomedical research and development. One involves the application to solid tissue, which is the basic application of this technique for the medical diagnosis. As this technique requires only 10 mg of the sample, it may be very useful in the routine clinical settings. The second application is for in vitro medical diagnostics where human blood serum is measured. The ability to measure fluid samples is also valuable in various biological experiments where a sufficient volume of sample for conventional analytical techniques cannot be provided. The third application leans toward the direct application of probe needles in living animals, where we can obtain real-time dynamics of metabolites or drugs in specific organs. In each application, we can infer the molecules that have been detected by MS or use artificial intelligence to obtain a medical diagnosis.

This article introduces sample preparation methods for a unique real-time analytical method based on the ambient mass spectrometry. This method lets us perform real-time analysis of the biological molecules in vivo without any special pretreatments.

Probuelektrosprey Iyonizasyon Kütle Spektrometresi için Örnek Hazırlama

Mass spectrometry (MS) is a powerful tool in analytical chemistry because it provides very accurate information about molecules, such as mass-to-charge ...