Diese Arbeit wurde vom Natural Sciences and Engineering Research Council of Canada, dem Fonds de Recherche du Quebec Nature et Technologie, der Canadian Foundation for Innovation und den Start-up-Fonds der McGill University unterstützt.

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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. 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. 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Wir haben nichts zu verraten.

Der in diesem Protokoll vorgestellte HDX-MS-Workflow bietet eine bemerkenswert robuste Plattform zur Kartierung der räumlichen Verteilung strukturdynamischer Elemente in Proteinen und zur Untersuchung, wie sich diese Dynamik als Reaktion auf Störungen (Ligandenbindung, Enzym-Mutagenese usw.) ändert. HDX-MS bietet mehrere deutliche Vorteile gegenüber anderen strukturbiologischen Ansätzen, die häufig zur Untersuchung der Konformationsdynamik verwendet werden. Vor allem werden nur geringe Mengen Aniis benötigt. Mithi...

Proteine sind strukturell dynamische Moleküle, die verschiedene Konformationen auf Zeitskalen abtasten, die von Bindungsschwingungen im Femtosekundenmaßstab bis hin zu Umlagerungen ganzer Proteindomänen reichen, die über viele Sekunden auftreten können1. Diese Konformationsschwankungen sind oft kritische Aspekte der Enzym-/Proteinfunktion. So sind beispielsweise konforme Veränderungen, die durch Ligandenbindung induziert werden, oft von entscheidender Bedeutung für die Modulation der Enzymfunktion, entweder durch die Organisation aktiver Standortrückstände, die für die Katalyse benötigt werden, die Definition von Substratbindungsstellen in sequenziellen kinetischen Mechanismen, die Abschirmung reaktiver Zwischenprodukte von der Umgebung oder durch Modulation der Enzymfunktion über allosterische Netzwerke. Jüngste Studien haben auch gezeigt, dass die konforme Dynamik während der gesamten Evolution konserviert werden kann und dass Störungen zu konservierten molekularen Bewegungen mit Veränderungen der Substratspezifität und der Entstehung neuer Enzymfunktionenkorreliertwerden können 2,3.
In den letzten Jahren hat sich die Wasserstoff-Deuterium-Austausch-Massenspektrometrie (HDX-MS) schnell als eine leistungsstarke Technik entwickelt, um zu untersuchen, wie Proteinkonformationslandschaften auf Störungen wie Ligandenbindung oder Mutagenese4,5,6,7reagieren. In einem typischen HDX-MS-Experiment (Abbildung 1) wird ein inD2O hergestelltes Protein in einen Puffer gegeben, der den Austausch von lösungsmittelaustauschbaren Protonen durch Deuteria auslöst. Die Wechselkursrate der Amid-Feuchtigkeit der Peptidbindungen hängt stark vom pH-Wert, der lokalen Aminosäuresequenz und der lokalen strukturellen Umgebung des Amids8ab. Amide, die mit Wasserstoffbindungswechselwirkungen (wie sie in α-Helices und β-Blättern vorhanden sind) tätig sind, tauschen sich langsamer aus als Amide in unstrukturierten Regionen des Proteins, die Massenlösungsmitteln ausgesetzt sind. Somit spiegelt das Ausmaß der Deuteriumaufnahme die Struktur des Enzyms wider. Enzyme, die konform dynamisch sind oder bei Ligandenbindung strukturelle Übergänge durchlaufen, würden eine messbare HDX-Antwort liefern.
Die mechanistische Grundlage für den langsamen Wechselkurs eines strukturierten Amids ist in Abbildung 25,8,9dargestellt. Um HDX zu durchlaufen, muss der strukturierte Bereich zunächst eine entfaltete Konformation vorübergehend abtasten, so dass die Lösungsmittelmoleküle, die den HDX-Austausch über einen bestimmten säure-basenchemischen Mechanismus katalysieren, Zugang zum austauschbaren Amid haben. Letztlich bestimmen die relativen Größen des chemischen Wechselkurses (kchem) und die Falt- und Umfaltraten (koffen und kschließen) die im ExperimentgemesseneHDX-Rate 5,8. Aus diesem einfachen kinetischen Modell geht klar hervor, dass das Ausmaß der Deuteriumaufnahme die zugrunde liegende Konformationsdynamik widerspiegelt (wie definiert durch koffen und kclose). Die meisten HDX-MS-Experimente werden in einem Bottom-up-Workflow durchgeführt, bei dem nach der Austauschreaktion das von Interesse kommende Protein in Peptide verdaut wird und die Deuteriumaufnahme durch jedes Peptid als Erhöhung der Masse7gemessen wird. Auf diese Weise ermöglicht HDX-MS die Zuordnung von Störungen der Enzym-Konformationsdynamik auf der lokalen räumlichen Skala von Peptiden, sodass der Forscher beurteilen kann, wie die Störung die Dynamik in verschiedenen Regionen des Enzyms von Interesse verändert.
Die Vorteile des HDX-MS-Ansatzes zur Aufklärung der Proteinstrukturdynamik sind zahlreich. Zunächst kann die Methode mit kleinen Mengen an nativem Protein oder auf Proteinkomplexen in Systemen mit quartärer Struktur10durchgeführt werden. Es ist nicht einmal notwendig, dass die im Test verwendete Enzympräparation hochgereinigt wird11,12, solange der Bottom-up-HDX-MS-Workflow eine ausreichende Anzahl von sicher identifizierten Peptiden bietet, die die Proteinsequenz von Interesse abdecken. Darüber hinaus kann HDX-MS Informationen über konforme Dynamiken unter nahezu nativen Bedingungen bereitstellen, ohne dass eine standortspezifische Proteinkennzeichnung erforderlich ist, wie sie in Einzelmolekülfluoreszenzstudien13verwendet würde, und es gibt keine Größenbeschränkung für den Protein- oder Proteinkomplex, die untersucht werden kann (was Ansätze wie Kernspinresonanz [NMR] Spektroskopie schwierig macht)7,14. Schließlich können zeitaufgelöste HDX-MS-Methoden eingesetzt werden, um intrinsisch ungeordnete Proteine zu untersuchen, die mit Röntgenkristallographie15,16,17,18schwer zu untersuchen sind. Die Hauptbeschränkung von HDX-MS ist, dass die Daten von geringer struktureller Auflösung sind. HDX-MS-Daten sind nützlich, um darauf hinzuweisen, wo sich die Konformationsdynamik ändert, und um gekoppelte Konformationsänderungen aufzudecken, aber sie bieten oft nicht viel Einblick in den genauen molekularen Mechanismus, der die beobachtete Veränderung antreibt. Jüngste Fortschritte in der Kombination von Elektronenfang-Dissoziationsmethoden mit Protein-HDX-MS-Daten haben gezeigt, dass Austauschstellen zu einzelnen Aminosäurerückständen19zugeordnet werden können, aber nachfolgende biochemische und strukturelle Studien sind immer noch häufig erforderlich, um Klarheit für Strukturmodelle zu schaffen, die von HDX-MS-Daten übermittelt werden.
Nachfolgend wird ein detailliertes Protokoll für die Entwicklung eines HDX-MS-Assays vorgestellt20. Die nachstehend vorgestellten Probenvorbereitungsprotokolle sollten allgemein für jedes Protein gelten, das eine gute Löslichkeit in wässrigen Puffern aufweist. Speziellere Probenvorbereitungsmethoden und HDX-MS-Workflows stehen für Proteine zur Verfügung, als in Gegenwart von Waschmitteln oder Phospholipiden21,22,23,24untersucht werden müssen. Instrumentale Einstellungen für die HDX-MS-Datenerfassung werden für ein hochauflösendes Quadrupol-Massenspektrometer beschrieben, das an das Flüssigchromatographiesystem gekoppelt ist. Daten von ähnlicher Komplexität und Auflösung könnten auf einem der handelsüblichen Flüssigchromatographie-Massenspektrometrie-Systeme (LC-MS) gesammelt werden. Wichtige Aspekte der Datenverarbeitung mit einem kommerziell erhältlichen Softwarepaket werden ebenfalls zur Verfügung gestellt. Wir stellen auch Richtlinien für die Datenerhebung und -analyse vor, die mit den Empfehlungen der breiteren HDX-MS-Community12übereinstimmen. Das beschriebene Protokoll wird verwendet, um die dynamischen strukturellen Eigenschaften von HalM2 zu untersuchen, einer Lanthipeptid-Synthetase, die die mehrstufige Reifung eines antimikrobiellen Peptids20katalysiert. Wir veranschaulichen, wie HDX-MS verwendet werden kann, um Substratbindungsstellen und allosterische Eigenschaften aufzudecken, die einer vorherigen Charakterisierung entgangen sind. Mehrere andere Protokolle zum Protein HDX-MS wurden in den letzten Jahren veröffentlicht25,26. Zusammen mit der vorliegenden Arbeit sollten diese früheren Beiträge dem Leser eine gewisse Flexibilität im experimentellen Design bieten.

<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

Die Wasserstoff-Deuterium-Austauschmassenspektrometrie (HDX-MS) ist eine leistungsfähige Methode zur biophysikalischen Charakterisierung von Enzymkonformationsveränderungen und Enzym-Substrat-Wechselwirkungen. Unter seinen vielen Vorteilen verbraucht HDX-MS nur geringe Mengen an Material, kann unter nahezu nativen Bedingungen ohne Enzym-/Substratkennzeichnung durchgeführt werden und kann räumlich aufgelöste Informationen über Enzymkonformationsdynamik liefern – auch für große Enzyme und Multiproteinkomplexe. Die Methode wird durch die Verdünnung des enzyms von Interesse in Puffer inD2O vorbereitet initiiert. Dies löst den Austausch von Protium in Peptidbindungsamiden (N-H) mit Deuterium (N-D) aus. An den gewünschten Austauschzeitpunkten werden Reaktions-Aliquots abgeschreckt, das Enzym in Peptide proteolysiert, die Peptide durch ultra-performance liquid chromatography (UPLC) getrennt und die Veränderung der Masse jedes Peptids (aufgrund des Austauschs von Wasserstoff gegen Deuterium) wird von MS aufgezeichnet. Die Menge der Deuteriumaufnahme durch jedes Peptid hängt stark von der lokalen Wasserstoffbindungsumgebung dieses Peptids ab. Peptide, die in sehr dynamischen Regionen des Enzymaustauschdeuteriums sehr schnell vorhanden sind, während Peptide aus gut geordneten Regionen viel langsamer austauschen. Auf diese Weise berichtet die HDX-Rate über die lokale Enzymkonformationsdynamik. Störungen der Deuteriumaufnahme in Gegenwart verschiedener Liganden können dann verwendet werden, um Ligandenbindungsstellen zu kartieren, allosterische Netzwerke zu identifizieren und die Rolle der Konformationsdynamik in der Enzymfunktion zu verstehen. Hier veranschaulichen wir, wie wir HDX-MS verwendet haben, um die Biosynthese einer Art von Peptid-Naturprodukten namens Lanthipeptide besser zu verstehen. Lanthipeptide sind genetisch kodierte Peptide, die posttranslational durch große, multifunktionale, konformational dynamische Enzyme modifiziert werden, die mit traditionellen strukturbiologischen Ansätzen schwer zu studieren sind. HDX-MS bietet eine ideale und anpassungsfähige Plattform zur Untersuchung der mechanistischen Eigenschaften dieser Enzymtypen.

Es ist notwendig, die Qualität der proteolytischen Verdauung und die Reproduzierbarkeit des Workflows für jeden Satz von Probeninjektionen zu bewerten. Daher ist es vor der Durchführung von HDX-MS-Assays wichtig, wirksame Bedingungen für die Proteolyse des Proteins von Interesse, für die Trennung von Peptiden mittels Reverse-Phase-Flüssigkeitschromatographie und Gasphasenionenmobilität sowie für den Nachweis von Peptiden mit MS zu schaffen. Zu diesem Zweck sollten zunächst die Referenzproben für das Protein von...

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

Lanthipeptid-Synthetasen katalysieren mehrstufige Reaktionen während der Biosynthese von Peptid-Naturprodukten. Hier beschreiben wir einen kontinuierlichen, Bottom-up, Wasserstoff-Deuterium-Austausch-Massenspektrometrie (HDX-MS) Workflow, der verwendet werden kann, um die Konformationsdynamik von Lanthipeptid-Synthetasen zu studieren, sowie andere ähnliche Enzyme, die an der Peptid-Naturproduktbiosynthese beteiligt sind.

Eine Wasserstoff-Deuterium-Austausch-Massenspektrometrie -Plattform (HDX-MS) zur Untersuchung biosynthetischer Peptidenzyme

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 Aufrufe.  McGill University. Lanthipeptid-Synthetasen katalysieren mehrstufige Reaktionen während der Biosynthese von Peptid-Naturprodukten. Hier beschreiben wir einen kontinuierlichen, Bottom-up, Wasserstoff-Deuterium-Austausch-Massenspektrometrie (HDX-MS) Workflow, der verwendet werden kann, um die Konformationsdynamik von Lanthipeptid-Synthetasen zu studieren, sowie andere ähnliche Enzyme, die an der Peptid-Naturproduktbiosynthese beteiligt sind.

Serie: 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.

Zeitaufgelöste Elektrospray-Ionisations Wasserstoff-Deuterium-Austausch-Massenspektrometrie zur Struktur Protein Studium und Dynamik

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

Forschung

Biochemie

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.

Auflösen von Affinity Purified Protein-Komplexen von Blue native PAGE und Protein Correlation Profilieren

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.

Lipid Droplet Isolierung für die quantitative Massenspektrometrie-Analyse

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.

Probenvorbereitung für Masse Spektrometrie-basierte Identifikation der RNA-bindende Regionen

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.

Optimale Vorbereitung von Formalin fixiert Proben für Peptid-Matrix basierten Assisted Laser Desorption/Ionisierung Massenspektrometrie Imaging-Workflows

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 des Redox-regulierten Chaperon Aktivität definieren und Mapping Konformationsänderungen auf Hsp33 mit Wasserstoff-Deuterium Austausch Massenspektrometrie

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.

Nachweis von Protein-Ubiquitinationsstellen durch Peptidanreicherung und Massenspektrometrie

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.

Nitropeptid Profilierung und Identifikation illustriert von 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 ...

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.

Eine Plasma-Probenvorbereitung für die Massenspektrometrie mit einer automatisierten Workstation

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.

Probenvorbereitung für Probe Elektrospray-Ionen-Massenspektrometrie

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