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Direct evidence for conformational dynamics in major histocompatibility complex class I molecules

Direct evidence for conformational dynamics in major histocompatibility complex class I molecules
Direct evidence for conformational dynamics in major histocompatibility complex class I molecules

Major histocompatibility complex class I molecules (MHC I) help protect jawed vertebrates by binding and presenting immunogenic peptides to cytotoxic T lymphocytes. Peptides are selected from a large diversity present in the endoplasmic reticulum. However, only a limited number of peptides complement the polymorphic MHC specificity determining pockets in a way that leads to high-affinity peptide binding and efficient antigen presentation. MHC I molecules possess an intrinsic ability to discriminate between peptides, which varies in efficiency between allotypes, but the mechanism of selection is unknown. Elucidation of the selection mechanism is likely to benefit future immune-modulatory therapies. Evidence suggests peptide selection involves transient adoption of alternative, presumably higher energy conformations than native peptide-MHC complexes. However, the instability of peptide-receptive MHC molecules has hindered characterization of such conformational plasticity. To investigate the dynamic nature of MHC, we refolded MHC proteins with peptides that can be hydrolyzed by UV light and thus released. We compared the resultant peptide-receptive MHC molecules with non-hydrolyzed peptide-loaded MHC complexes by monitoring the exchange of hydrogen for deuterium in solution. We found differences in hydrogen-deuterium exchange between peptide-loaded and peptide-receptive molecules that were negated by the addition of peptide to peptide-receptive MHC molecules. Peptide hydrolysis caused significant increases in hydrogen-deuterium exchange in sub-regions of the peptide-binding domain and smaller increases elsewhere, including in the α3 domain and the non-covalently associated β2-microglobulin molecule, demonstrating long-range dynamic communication. Comparing two MHC allotypes revealed allotype-specific differences in hydrogen-deuterium exchange, consistent with the notion that MHC I plasticity underpins peptide selection.

Animals, Antigen Presentation, Binding Sites, Chickens, Deuterium Exchange Measurement, Histocompatibility Antigens Class I/chemistry, Peptides/metabolism, Protein Binding, Protein Conformation, Protein Folding, Ultraviolet Rays
1083-351X
20255-20269
van Hateren, Andy
e345fa3c-d89c-4b91-947e-c1d818cc7f71
Anderson, Malcolm
57515f5d-235e-42bc-924c-93bf13605bb0
Bailey, Alistair
541e2cd9-ac72-4058-9293-def64fc2c284
Werner, Jörn M
1b02513a-8310-4f4f-adac-dc2a466bd115
Skipp, Paul
1ba7dcf6-9fe7-4b5c-a9d0-e32ed7f42aa5
Elliott, Tim
16670fa8-c2f9-477a-91df-7c9e5b453e0e
van Hateren, Andy
e345fa3c-d89c-4b91-947e-c1d818cc7f71
Anderson, Malcolm
57515f5d-235e-42bc-924c-93bf13605bb0
Bailey, Alistair
541e2cd9-ac72-4058-9293-def64fc2c284
Werner, Jörn M
1b02513a-8310-4f4f-adac-dc2a466bd115
Skipp, Paul
1ba7dcf6-9fe7-4b5c-a9d0-e32ed7f42aa5
Elliott, Tim
16670fa8-c2f9-477a-91df-7c9e5b453e0e

van Hateren, Andy, Anderson, Malcolm, Bailey, Alistair, Werner, Jörn M, Skipp, Paul and Elliott, Tim (2017) Direct evidence for conformational dynamics in major histocompatibility complex class I molecules. Journal of Biological Chemistry, 292 (49), 20255-20269. (doi:10.1074/jbc.M117.809624).

Record type: Article

Abstract

Major histocompatibility complex class I molecules (MHC I) help protect jawed vertebrates by binding and presenting immunogenic peptides to cytotoxic T lymphocytes. Peptides are selected from a large diversity present in the endoplasmic reticulum. However, only a limited number of peptides complement the polymorphic MHC specificity determining pockets in a way that leads to high-affinity peptide binding and efficient antigen presentation. MHC I molecules possess an intrinsic ability to discriminate between peptides, which varies in efficiency between allotypes, but the mechanism of selection is unknown. Elucidation of the selection mechanism is likely to benefit future immune-modulatory therapies. Evidence suggests peptide selection involves transient adoption of alternative, presumably higher energy conformations than native peptide-MHC complexes. However, the instability of peptide-receptive MHC molecules has hindered characterization of such conformational plasticity. To investigate the dynamic nature of MHC, we refolded MHC proteins with peptides that can be hydrolyzed by UV light and thus released. We compared the resultant peptide-receptive MHC molecules with non-hydrolyzed peptide-loaded MHC complexes by monitoring the exchange of hydrogen for deuterium in solution. We found differences in hydrogen-deuterium exchange between peptide-loaded and peptide-receptive molecules that were negated by the addition of peptide to peptide-receptive MHC molecules. Peptide hydrolysis caused significant increases in hydrogen-deuterium exchange in sub-regions of the peptide-binding domain and smaller increases elsewhere, including in the α3 domain and the non-covalently associated β2-microglobulin molecule, demonstrating long-range dynamic communication. Comparing two MHC allotypes revealed allotype-specific differences in hydrogen-deuterium exchange, consistent with the notion that MHC I plasticity underpins peptide selection.

Text
J. Biol. Chem.-2017-van Hateren-jbc.M117.809624 - Accepted Manuscript
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More information

Accepted/In Press date: 11 October 2017
e-pub ahead of print date: 11 October 2017
Published date: 8 December 2017
Keywords: Animals, Antigen Presentation, Binding Sites, Chickens, Deuterium Exchange Measurement, Histocompatibility Antigens Class I/chemistry, Peptides/metabolism, Protein Binding, Protein Conformation, Protein Folding, Ultraviolet Rays

Identifiers

Local EPrints ID: 416201
URI: http://eprints.soton.ac.uk/id/eprint/416201
ISSN: 1083-351X
PURE UUID: a2a8795e-9a48-4c14-9a99-ea9da3558a81
ORCID for Andy van Hateren: ORCID iD orcid.org/0000-0002-3915-0239
ORCID for Alistair Bailey: ORCID iD orcid.org/0000-0003-0023-8679
ORCID for Jörn M Werner: ORCID iD orcid.org/0000-0002-4712-1833
ORCID for Paul Skipp: ORCID iD orcid.org/0000-0002-2995-2959
ORCID for Tim Elliott: ORCID iD orcid.org/0000-0003-1097-0222

Catalogue record

Date deposited: 07 Dec 2017 17:30
Last modified: 26 Nov 2021 06:23

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Contributors

Author: Malcolm Anderson
Author: Alistair Bailey ORCID iD
Author: Jörn M Werner ORCID iD
Author: Paul Skipp ORCID iD
Author: Tim Elliott ORCID iD

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