这项工作得到了加拿大自然科学和工程研究理事会、魁北克自然与技术基金会、加拿大创新基金会和麦吉尔大学创业基金的支持。

<ol>
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L., Deng, Y., Zhang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+non-covalent+structure+of+proteins+by+amide+hydrogen+exchange+and+mass+spectrometry.">Probing the non-covalent structure of proteins by amide hydrogen exchange and mass spectrometry.</a> Journal of Mass Spectrometry. 32 (2), 135-146 (1997).</li><li>Masson, G. 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=Recommendations+for+performing,+interpreting+and+reporting+hydrogen+deuterium+exchange+mass+spectrometry+(HDX-MS)+experiments.">Recommendations for performing, interpreting and reporting hydrogen deuterium exchange mass spectrometry (HDX-MS) experiments.</a> Nature Methods. 16 (7), 595-602 (2019).</li><li>Liu, J., 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=An+Efficient+Site-Specific+Method+for+Irreversible+Covalent+Labeling+of+Proteins+with+a+Fluorophore.">An Efficient Site-Specific Method for Irreversible Covalent Labeling of Proteins with a Fluorophore.</a> Scientific Reports. 5, 16883 (2015).</li><li>Marion, 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=Overcoming+the+overlap+problem+in+the+assignment+of+proton+NMR+spectra+of+larger+proteins+by+use+of+three-dimensional+heteronuclear+proton-nitrogen-15+Hartmann-Hahn-multiple+quantum+coherence+and+nuclear+Overhauser-multiple+quantum+coherence+spectroscopy:+application+to+interleukin+1.beta.">Overcoming the overlap problem in the assignment of proton NMR spectra of larger proteins by use of three-dimensional heteronuclear proton-nitrogen-15 Hartmann-Hahn-multiple quantum coherence and nuclear Overhauser-multiple quantum coherence spectroscopy: application to interleukin 1.beta.</a> Biochemistry. 28 (15), 6150-6156 (1989).</li><li>Balasubramaniam, D., Komives, E. 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. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insights+into+the+Dynamic+Structural+Properties+of+a+Lanthipeptide+Synthetase+using+Hydrogen-Deuterium+Exchange+Mass+Spectrometry.">Insights into the Dynamic Structural Properties of a Lanthipeptide Synthetase using Hydrogen-Deuterium Exchange Mass Spectrometry.</a> Journal of the American Chemical Society. 141 (37), 14661-14672 (2019).</li><li>Hebling, C. 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=Conformational+analysis+of+membrane+proteins+in+phospholipid+bilayer+nanodiscs+by+hydrogen+exchange+mass+spectrometry.">Conformational analysis of membrane proteins in phospholipid bilayer nanodiscs by hydrogen exchange mass spectrometry.</a> Analytical Chemistry. 82 (13), 5415-5419 (2010).</li><li>Duc, N. 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. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analyzing+protein+dynamics+using+hydrogen+exchange+mass+spectrometry.">Analyzing protein dynamics using hydrogen exchange mass spectrometry.</a> Journal of Visualized Experiments. (81), e50839 (2013).</li><li>Lento, 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=Time-resolved+ElectroSpray+Ionization+Hydrogen-deuterium+Exchange+Mass+Spectrometry+for+Studying+Protein+Structure+and+Dynamics.">Time-resolved ElectroSpray Ionization Hydrogen-deuterium Exchange Mass Spectrometry for Studying Protein Structure and Dynamics.</a> Journal of Visualized Experiments. (122), e55464 (2017).</li><li>Schowen, K. B., Schowen, R. 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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我们没有什么可透露的。

本协议中介绍的 HDX-MS 工作流程为绘制蛋白质结构动态元素的空间分布图和调查这些动力学如何因扰动（脂结合、酶突变等）而变化提供了非常强大的平台。HDX-MS 与其他通常用于研究构象动力学的结构生物学方法相比具有几个明显的优势。最值得注意的是，只需要少量的蛋白质。使用此处描述的工作流程，1 mL 1 μM 蛋白质样本为包含 5 个交换时间点的三方 HDX 反应提供了足够的材料。此外，兴趣蛋...

蛋白质是结构动力学分子，在时间尺度上采样不同的构象，从女性到第二级的键振动到整个蛋白质域的重新排列，这些排列可以在多秒1内发生。这些构象波动通常是酶/蛋白质功能的关键方面。例如，由配体结合引起的构象变化通常对于调节酶功能至关重要，无论是组织催化所需的活动站点残留物、在顺序动能机制中定义基板结合位点、保护反应中间体免受环境影响，还是通过全石器网络调节酶功能。最近的研究还表明，在整个进化过程中可以保存符合性动力学，而对保存分子运动的扰动可以与基质特异性的变化和新酶功能2、3的出现相关。
近年来，氢-铀交换质谱仪（HDX-MS）迅速成为探索蛋白质构象景观如何对配体结合或突变4、5、6、7等扰动做出反应的有力技术。在典型的HDX-MS实验（图1）中，一种感兴趣的蛋白质被放入D2O制备的缓冲器中，这触发了可溶剂交换质子与 deuteria 的替代。肽债券的交换率在很大程度上取决于pH度、局部氨基酸序列和8号辣椒的局部结构环境。从事氢粘结相互作用的中位（如存在于α螺旋和β片中）的交换速度比暴露于散装溶剂的蛋白质非结构化区域中的中位要慢。因此，铀吸收的程度反映了酶的结构。符合动态的酶，或在配体结合后进行结构转换的酶，将有望产生可测量的HDX响应。
结构化中间体缓慢汇率的机械基础见图25、8、9。为了进行HDX，结构区域必须首先对展开的构象进行瞬时采样，以便通过特定的酸/碱基化学机制促进HDX交换的溶剂分子能够进入可交换的中间体。最终，化学汇率（k化学）的相对幅度和折叠和重折叠率（k打开和k关闭）决定了实验5、8中测量的HDX汇率。从这个简单的动能模型中，很明显，铀吸收的程度将反映潜在的构象动力学（如k开和k关闭的定义）。大多数HDX-MS实验都是在自下而上的工作流程中进行的，在交流反应之后，兴趣蛋白被消化成肽，每个肽的吸乳量被测量为质量7的增加。通过这种方式，HDX-MS 允许在肽的局部空间尺度上映射酶构象动力学的扰动，使研究人员能够评估扰动如何改变感兴趣的酶不同区域的动力学。
HDX-MS方法用于阐明蛋白质结构动力学的优点是多种多方面的。首先，该方法可以在具有第四纪结构10的系统中用少量的原生蛋白质或蛋白质复合物进行。只要自下而上的HDX-MS工作流程提供足够数量的自信识别肽，涵盖感兴趣的蛋白质序列，就根本不需要在检测中使用的酶制剂进行高度纯化。此外，HDX-MS可以提供近原生条件下的构象动力学信息，而无需像单分子荧光研究13中那样使用部位特异性蛋白质标签，并且对可以研究的蛋白质或蛋白质复合物没有大小限制（这使得核磁共振[NMR]光谱学等方法具有挑战性）7，14。最后，可以采用时间解决的HDX-MS方法来研究内在紊乱的蛋白质，这些蛋白质很难用X射线晶体学15、16、17、18来研究。HDX-MS 的主要限制是数据结构分辨率低。HDX-MS 数据可用于指出构象动力学的变化位置，并揭示耦合的构象变化，但它们通常不会提供对驱动观测变化的精确分子机制的深入了解。电子捕获分离方法与蛋白质HDX-MS数据相结合的最新进展表明，将交换点绘制为单一氨基酸残留物19有希望，但还需要进行后续生化和结构研究，以便为HDX-MS数据转发的结构模型提供清晰度。
下面，提出了一个详细的协议，为开发HDX-MS检测是20。下面介绍的样品制备协议通常应适用于在水性缓冲中表现出良好溶解性的任何蛋白质。更专业的样品制备方法和HDX-MS工作流程可用于蛋白质比需要检测在洗涤剂或磷脂的存在21，22，23，24。HDX-MS 数据收集的仪器设置被描述为高分辨率四倍飞行时间质谱仪与液相色谱系统相结合。可以在一些市售的液相色谱-质谱 （LC-MS） 系统中的任何一个系统上收集具有类似复杂性和分辨率的数据。还提供了使用市售软件包进行数据处理的关键方面。此外，我们亦提供与更广泛的HDX-MS社区12的建议相一致的数据收集及分析指引。所述协议用于研究HalM2的动态结构特性，HalM2是一种促进抗菌肽天然产品20的多步成熟。我们说明了如何使用 HDX-MS 来揭示基板绑定站点和未采用以前特征的异体特性。近年来，关于蛋白质HDX-MS的其他几项协议已经发表25，26。结合目前的工作，这些早期的贡献应该为读者提供一些实验设计的灵活性。

<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

氢-铀交换质谱仪（HDX-MS）是酶构象变化和酶基质相互作用生物物理特征的有力方法。HDX-MS 的诸多优点中，仅消耗少量材料，无需酶/基质标签即可在近原生条件下进行，并且可以提供酶构象动力学空间解决信息−甚至用于大型酶和多蛋白复合物。该方法由将兴趣酶稀释到 D2O 中准备的缓冲器中启动。这触发了肽键（N-H）与铀（N-D）的蛋白交换。在所需的交换时间点，反应液被淬火，酶被蛋白酶分解成肽，肽通过超性能液相色谱 （UPLC） 分离，并且每个肽的质量变化（由于氢气交换为铀）由 MS 记录。每种肽吸收的钚量在很大程度上取决于该肽的局部氢结合环境。肽存在于酶交换的非常活跃的区域非常快，而从有序区域提取的肽的交换速度要慢得多。通过这种方式，HDX 速率报告了局部酶构象动力学。然后，在不同配体存在的情况下，对脱脂吸收水平进行扰动，可用于绘制配体绑定位点的地图，识别同位素网络，并了解构象动力学在酶功能中的作用。在这里，我们说明了我们如何使用HDX-MS来更好地了解一种叫做兰西肽的肽天然产品的生物合成。Lanthipeptides 是基因编码肽，通过大型、多功能、符合性动态酶进行转化后进行修饰，这些酶很难用传统的结构生物学方法进行研究。HDX-MS 为研究这些类型的酶的机械特性提供了一个理想且适应性的平台。

有必要评估蛋白催化消化的质量以及每组样品注射工作流程的可重复性。因此，在进行HDX-MS检测之前，必须为兴趣蛋白的蛋白分析、使用反相液相色谱和气体相离子流动性分离肽以及使用MS检测肽建立有效条件。为此目的，应首先调查感兴趣的蛋白质的参考样本（在没有贫血的情况下收集）（第3节）。图3A−C中的色谱数据显示了HalM2兰西肽合成酶三个参考样本的...

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

在肽天然产品的生物合成过程中，兰西肽合成器催化多步反应。在这里，我们描述了一个连续的，自下而上的，氢-钚交换质谱仪（HDX-MS）的工作流程，可用于研究兰西肽合成器的构象动力学，以及肽天然产品生物合成中涉及的其他类似酶。

氢-铀交换质谱仪（HDX-MS）平台，用于研究肽生物合成酶

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 次观看.  McGill University. 在肽天然产品的生物合成过程中，兰西肽合成器催化多步反应。在这里，我们描述了一个连续的，自下而上的，氢-钚交换质谱仪（HDX-MS）的工作流程，可用于研究兰西肽合成器的构象动力学，以及肽天然产品生物合成中涉及的其他类似酶。

视频: 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.

时间分辨电喷雾电离氢氘交换质谱用于研究蛋白质结构与动态

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

科研

生物化学

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.

解决由蓝变性PAGE和蛋白质相关剖析亲和纯化的蛋白复合物

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.

脂滴隔离定量质谱分析

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.

RNA 结合区质量谱鉴定的样品制备

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.

多肽基基质辅助激光解吸/电离质谱成像中福尔马林固定样品的优化制备工作流

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.

用氢-氘交换质谱法定义 Hsp33's 氧化还原调节陪护活动和 Hsp33 映射构象变化

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.

通过肽浓缩和质谱检测蛋白质泛化位点检测

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.

血管紧张蛋白II图解的硝酸分析与鉴定

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.

使用自动工作站进行质谱测量的等离子体样品制备

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.

探头电喷电镀质谱的样品制备

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