330 research outputs found
Structural mass spectrometry approaches to understand multidrug efflux systems
Get PDFMultidrug efflux pumps are ubiquitous across both eukaryotes and prokaryotes, and have major implications in antimicrobial and multidrug resistance. They reside within cellular membranes and have proven difficult to study owing to their hydrophobic character and relationship with their compositionally complex lipid environment. Advances in structural mass spectrometry (MS) techniques have made it possible to study these systems to elucidate critical information on their structure–function relationships. For example, MS techniques can report on protein structural dynamics, stoichiometry, connectivity, solvent accessibility, and binding interactions with ligands, lipids, and other proteins. This information proving powerful when used in conjunction with complementary structural biology methods and molecular dynamics (MD) simulations. In the present review, aimed at those not experts in MS techniques, we report on the current uses of MS in studying multidrug efflux systems, practical considerations to consider, and the future direction of the field. In the first section, we highlight the importance of studying multidrug efflux proteins, and introduce a range of different MS techniques and explain what information they yield. In the second section, we review recent studies that have utilised MS techniques to study and characterise a range of different multidrug efflux systems
Using hydrogen/deuterium exchange mass spectrometry to understand bacterial membrane efflux proteins
No full textBacterial multidrug efflux pumps play major roles in antibiotic and multidrug resistance as well as fulfilling many important physiological functions. These molecular machines are highly dynamic, with structural malleability at the core of their action, and elaborating their conformational features can provide insight into the mechanisms underpinning their activities and responses to transport substrates and inhibitors. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a structural biology assay used to monitor protein backbone dynamics and is capable of elucidating conformational signatures that define function and fold. In recent years, HDX-MS methods have advanced, making its use more amenable to the study of membrane proteins, yet experimental challenges remain. In this chapter, we provide background on HDX-MS, its limitations, and discussions around experimental design and optimization for studying efflux pump proteins, including its application to study membrane proteins in lipid environments. To demonstrate its utility, we provide an original case study on AcrB inhibition by an efflux pump inhibitor (MBX-3756), employing membrane-scaffold protein lipid nanodiscs, revealing perturbation of backbone motions distinguishing of hydrophobic-trap targeting inhibitory action. This chapter can serve as a guide for designing HDX-MS investigations on efflux pump proteins and membrane proteins in general.</p
DaF und digitale Medien : ein Interview mit Dietmar Rösler
No full textDer Gießener Professor und Autor der Bücher "E-Learning Fremdsprachen - eine kritische Einführung" und "Deutsch als Fremdsprache: Eine Einführung", Dietmar Rösler, spricht im Interview über seine Ideen zum Einsatz digitaler Medien im DaF-Unterricht und seine Erfahrungen als Hochschulprofessor mit der Digitalisierung der Lehre vor und während der Corona-Pandemie in Deutschland. Dabei skizziert er mögliche Konsequenzen aus der Krise für unterschiedliche fremdsprachliche Lehr- und Lernszenarien sowie für Veränderungen in der Aus- und Fortbildung von DaF-Lehrenden. Dietmar Rösler beschreibt in diesem Interview auch seine Zukunftsvision zu den Lehrwerken in einer zunehmenden digitalisierten Welt.Dietmar Rösler, professor and author of the books "E-Learning Fremdsprachen - eine kritische Einführung" and "Deutsch als Fremdsprache: Eine Einführung", talks in an interview about his ideas on the use of digital media in teaching German as a foreign language and his experiences as a university professor with the digitization of teaching before and during the Corona pandemic in Germany. He outlines possible consequences of the crisis for different foreign language teaching and learning scenarios as well as for changes in the training and further education of teachers of German as a foreign language. Dietmar Rösler also describes in this interview his vision of the future of textbooks in an increasingly digitalized world.Dietmar Rösler, professor e autor dos livros "E-Learning Fremdsprachen - eine kritische Einführung" e "Deutsch als Fremdsprache: Eine Einführung", fala em uma entrevista sobre suas idéias sobre o uso de mídias digitais no ensino do alemão como língua estrangeira e suas experiências como professor universitário com a digitalização do ensino antes e durante a pandemia de Corona na Alemanha. Ele delineia possíveis consequências da crise para diferentes cenários de ensino e aprendizagem de línguas estrangeiras, bem como para mudanças na formação e na educação continuada de professores de alemão como língua estrangeira. Dietmar Rösler também descreve nesta entrevista sua visão sobre o futuro dos livros didáticos em um mundo cada vez mais digitalizado
Who are the Disciples and Admirers of an Author?
No full textWebcast sponsored by the Irving K. Barber Learning Centre and hosted by SLAIS. Recitation (the act of citing a given author or her/his works multiple times) provides an indication of the influence of a cited author. This study investigated patterns of citation and recitation across frequently cited authors' works to better understand how broadly citers have been influenced by cited authors and their publications. Dietmar Wolfram is Interim Dean & Professor School of Information Studies, University of Wisconsin-Milwaukee.Arts, Faculty ofLibrary, Archival and Information Studies (SLAIS), School ofUnreviewedFacult
Chromatographic Phospholipid Trapping for Automated H/D Exchange Mass Spectrometry of Membrane Protein–Lipid Assemblies
No full textLipid interactions modulate the function, folding, structure,
and
organization of membrane proteins. Hydrogen/deuterium exchange mass
spectrometry (HDX-MS) has emerged as a useful tool to understand the
structural dynamics of these proteins within lipid environments. Lipids,
however, have proven problematic for HDX-MS analysis of membrane-embedded
proteins due to their presence of impairing proteolytic digestion,
causing liquid chromatography column fouling, ion suppression, and/or
mass spectral overlap. Herein, we describe the integration of a chromatographic
phospholipid trap column into the HDX-MS apparatus to enable online
sample delipidation prior to protease digestion of deuterium-labeled
protein–lipid assemblies. We demonstrate the utility of this
method on membrane scaffold protein–lipid nanodiscboth
empty and loaded with the ∼115 kDa transmembrane protein AcrBproving
efficient and automated phospholipid capture with minimal D-to-H back-exchange,
peptide carry-over, and protein loss. Our results provide insights
into the efficiency of phospholipid capture by ZrO2-coated
and TiO2 beads and describe how solution conditions can
be optimized to maximize not only the performance of our online but
also the existing offline, delipidation workflows for HDX-MS. We envision
that this HDX-MS method will significantly ease membrane protein analysis,
allowing to better interrogate their dynamics in artificial lipid
bilayers or even native cell membranes
Structural dynamics in the evolution of SARS-CoV-2 spike glycoprotein - deuterium uptake plots
No full textDeuterium uptake plots of HDX-MS data sets contained in "Structural dynamics in the evolution of SARS-CoV-2 spike glycoprotein"
Valeria Calvaresi*, Antoni G. Wrobel*, Joanna Toporowska, Dietmar Hammerschmid, Katie J. Doores, Richard T. Bradshaw, Ricardo B. Parsons, Donald J. Benton, Chloë Roustan, Eamonn Reading, Michael H. Malim, Steven J. Gamblin, Argyris Politis*
Nature Communications, March 2023</p
Rezension: "Niegeschichte. Science Fiction als Kunst- und Denkmaschine" von Dietmar Dath
Get PDFDer Journalist und Science Fiction-Autor Dietmar Dath legt mit Niegeschichte eine umfassende Untersuchung seines Lieblingsgenres vor: Von ihren Anfängen bis zur Gegenwart werden Funktionsweisen der Science Fiction herausgearbeitet und mit der eigens adaptierten „funktorialen Literaturanalyse“ zerlegt. Seine offensichtliche Begeisterung für das Genre den Lesenden zu vermitteln, gelingt ihm dabei leider nicht.With Niegeschichte, journalist and science fiction author Dietmar Dath presents a comprehensive examination of his favorite genre: From its beginnings to the present, he elaborates on ways in which science fiction functions and dissects them with his specially adapted “functorial literature analysis”. Unfortunately, he does not succeed in conveying his obvious enthusiasm for the genre to the reader
German as a foreing language and digital media: An interview with Dietmar Rösler
No full textDer Gießener Professor und Autor der Bücher „E-Learning Fremdsprachen – eine kritische Einführung“ und „Deutsch als Fremdsprache: Eine Einführung“, Dietmar Rösler, spricht im Interview über seine Ideen zum Einsatz digitaler Medien im DaF-Unterricht und seine Erfahrungen als Hochschulprofessor mit der Digitalisierung der Lehre vor und während der Corona-Pandemie in Deutschland. Dabei skizziert er mögliche Konsequenzen aus der Krise für unterschiedliche fremdsprachliche Lehr- und Lernszenarien sowie für Veränderungen in der Aus- und Fortbildung von DaF-Lehrenden. Dietmar Rösler beschreibt in diesem Interview auch seine Zukunftsvision zu den Lehrwerken in einer zunehmenden digitalisierten Welt.Der Gießener Professor und Autor der Bücher „E-Learning Fremdsprachen – eine kritische Einführung“ und „Deutsch als Fremdsprache: Eine Einführung“, Dietmar Rösler, spricht im Interview über seine Ideen zum Einsatz digitaler Medien im DaF-Unterricht und seine Erfahrungen als Hochschulprofessor mit der Digitalisierung der Lehre vor und während der Corona-Pandemie in Deutschland. Dabei skizziert er mögliche Konsequenzen aus der Krise für unterschiedliche fremdsprachliche Lehr- und Lernszenarien sowie für Veränderungen in der Aus- und Fortbildung von DaF-Lehrenden. Dietmar Rösler beschreibt in diesem Interview auch seine Zukunftsvision zu den Lehrwerken in einer zunehmenden digitalisierten Welt.Dietmar Rösler, professor and author of the books "E-Learning Fremdsprachen - eine kritische Einführung" and "Deutsch als Fremdsprache: Eine Einführung", talks in an interview about his ideas on the use of digital media in teaching German as a foreign language and his experiences as a university professor with the digitization of teaching before and during the Corona pandemic in Germany. He outlines possible consequences of the crisis for different foreign language teaching and learning scenarios as well as for changes in the training and further education of teachers of German as a foreign language. Dietmar Rösler also describes in this interview his vision of the future of textbooks in an increasingly digitalized world
Droplet microfluidic hydrogen/deuterium exchange for investigating protein dynamics with millisecond precision
No full textHydrogen/deuterium exchange (HDX) methods for studying protein dynamics would benefit from millisecond-scale incubations to probe intrinsically disordered proteins, highly dynamic regions and conformation changes. Here we investigate droplet microfluidics for rapid mixing to trigger D2O labelling, uniform incubations and rapid droplet merging for acid quenching in advance of mass spectrometry. A surfactant-free merging approach combining expansion elements for synchronised droplet collision proved robust. The high diffusive flux of D2O and protons enable microsecond mixing to trigger and arrest D2O labelling, respectively, affording the possibility of single millisecond incubations. Droplet HDX processors were used to measure the fast uptake characteristics of a model peptide. Forward exchange measurements demonstrate D2O labelling to be the rate-limiting step, in essence defining 10 milliseconds as the minimum practical incubation time. With the ability to access millisecond time scales the fast dynamics of calmodulin, a model of calcium-triggered allostery with rapid conformational switching, was investigated. Fast reorganisation of the EF-hand motifs provoked by calcium binding was observed. The millisecond precision of droplet microfluidic HDX paves the way to advance understanding of protein structural dynamics
- …
