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Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms

[Image: see text] Aromatic ring flips are a hallmark of protein dynamics. They are experimentally studied by NMR spectroscopy, where recent advances have led to improved characterization across a wide range of time scales. Results on different proteins have been interpreted as continuous diffusive r...

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Autores principales: Dreydoppel, Matthias, Akke, Mikael, Weininger, Ulrich
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9574926/
https://www.ncbi.nlm.nih.gov/pubmed/36180044
http://dx.doi.org/10.1021/acs.jpcb.2c05097
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author Dreydoppel, Matthias
Akke, Mikael
Weininger, Ulrich
author_facet Dreydoppel, Matthias
Akke, Mikael
Weininger, Ulrich
author_sort Dreydoppel, Matthias
collection PubMed
description [Image: see text] Aromatic ring flips are a hallmark of protein dynamics. They are experimentally studied by NMR spectroscopy, where recent advances have led to improved characterization across a wide range of time scales. Results on different proteins have been interpreted as continuous diffusive ring rotations or jumplike flips, leading to diverging views of the protein interior as being fluidlike or solidlike, respectively. It is challenging to distinguish between these mechanisms and other types of conformational exchange because chemical-shift-mediated line broadening provides only conclusive evidence for ring flips only if the system can be moved from the slow- to intermediate/fast-exchange regime. Moreover, whenever the chemical shift difference between the two symmetry-related sites is close to zero, it is not generally possible to determine the exchange time scale. Here we resolve these issues by measuring residual dipolar coupling (RDC)-mediated exchange contributions using NMR relaxation dispersion experiments on proteins dissolved in dilute liquid crystalline media. Excellent agreement is found between the experimental difference in RDC between the two symmetry-related sites and the value calculated from high-resolution X-ray structures, demonstrating that dynamics measured for F52 in the B1 domain of protein G reports on distinct, jumplike flips rather than other types of conformational exchange.
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spelling pubmed-95749262022-10-18 Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms Dreydoppel, Matthias Akke, Mikael Weininger, Ulrich J Phys Chem B [Image: see text] Aromatic ring flips are a hallmark of protein dynamics. They are experimentally studied by NMR spectroscopy, where recent advances have led to improved characterization across a wide range of time scales. Results on different proteins have been interpreted as continuous diffusive ring rotations or jumplike flips, leading to diverging views of the protein interior as being fluidlike or solidlike, respectively. It is challenging to distinguish between these mechanisms and other types of conformational exchange because chemical-shift-mediated line broadening provides only conclusive evidence for ring flips only if the system can be moved from the slow- to intermediate/fast-exchange regime. Moreover, whenever the chemical shift difference between the two symmetry-related sites is close to zero, it is not generally possible to determine the exchange time scale. Here we resolve these issues by measuring residual dipolar coupling (RDC)-mediated exchange contributions using NMR relaxation dispersion experiments on proteins dissolved in dilute liquid crystalline media. Excellent agreement is found between the experimental difference in RDC between the two symmetry-related sites and the value calculated from high-resolution X-ray structures, demonstrating that dynamics measured for F52 in the B1 domain of protein G reports on distinct, jumplike flips rather than other types of conformational exchange. American Chemical Society 2022-09-30 2022-10-13 /pmc/articles/PMC9574926/ /pubmed/36180044 http://dx.doi.org/10.1021/acs.jpcb.2c05097 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by-nc-nd/4.0/Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Dreydoppel, Matthias
Akke, Mikael
Weininger, Ulrich
Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title_full Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title_fullStr Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title_full_unstemmed Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title_short Characterizing Fast Conformational Exchange of Aromatic Rings Using Residual Dipolar Couplings: Distinguishing Jumplike Flips from Other Exchange Mechanisms
title_sort characterizing fast conformational exchange of aromatic rings using residual dipolar couplings: distinguishing jumplike flips from other exchange mechanisms
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9574926/
https://www.ncbi.nlm.nih.gov/pubmed/36180044
http://dx.doi.org/10.1021/acs.jpcb.2c05097
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