Molecular characterization of the interaction between human IgG and the M-related proteins from Streptococcus pyogenes.


Proctor, Emma-Jayne ORCID: 0000-0002-9229-7694, Frost, Hannah R, Satapathy, Sandeep, Botquin, Gwenaëlle, Urbaniec, Joanna ORCID: 0000-0002-7186-9366, Gorman, Jody ORCID: 0000-0001-9824-4203, De Oliveira, David MP ORCID: 0000-0002-5085-7163, McArthur, Jason, Davies, Mark R, Botteaux, Anne et al (show 2 more authors) (2024) Molecular characterization of the interaction between human IgG and the M-related proteins from Streptococcus pyogenes. The Journal of biological chemistry, 300 (2). 105623-.

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Abstract

Group A Streptococcal M-related proteins (Mrps) are dimeric α-helical-coiled-coil cell membrane-bound surface proteins. During infection, Mrp recruit the fragment crystallizable region of human immunoglobulin G via their A-repeat regions to the bacterial surface, conferring upon the bacteria enhanced phagocytosis resistance and augmented growth in human blood. However, Mrps show a high degree of sequence diversity, and it is currently not known whether this diversity affects the Mrp-IgG interaction. Herein, we report that diverse Mrps all bind human IgG subclasses with nanomolar affinity, with differences in affinity which ranged from 3.7 to 11.1 nM for mixed IgG. Using surface plasmon resonance, we confirmed Mrps display preferential IgG-subclass binding. All Mrps were found to have a significantly weaker affinity for IgG3 (p < 0.05) compared to all other IgG subclasses. Furthermore, plasma pulldown assays analyzed via Western blotting revealed that all Mrp were able to bind IgG in the presence of other serum proteins at both 25 °C and 37 °C. Finally, we report that dimeric Mrps bind to IgG with a 1:1 stoichiometry, enhancing our understanding of this important host-pathogen interaction.

Item Type: Article
Uncontrolled Keywords: Humans, Streptococcus pyogenes, Bacterial Proteins, Bacterial Outer Membrane Proteins, Immunoglobulin G, Carrier Proteins
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 26 Mar 2024 11:12
Last Modified: 26 Mar 2024 15:30
DOI: 10.1016/j.jbc.2023.105623
Open Access URL: https://doi.org/10.1016/j.jbc.2023.105623
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3179976
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