Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin

Phillips-Jones, Mary K.; Channell, Guy Andrew; Kelsall, Claire J.; Hughes, Charlotte S.; Ashcroft, Alison E.; Patching, Simon G.; Dinu, Vlad; Gillis, Richard B.; Adams, Gary G.; Harding, Stephen E.

Abstract

VanA-type resistance to glycopeptide antibiotics in clinical enterococci is regulated by the VanSARA two-component signal transduction system. The nature of the molecular ligand that is recognised by the VanSA sensory component has not hitherto been identified. Here we employ purified, intact and active VanSA membrane protein (henceforth referred to as VanS) in analytical ultracentrifugation experiments to study VanS oligomeric state and conformation in the absence and presence of vancomycin. A combination of sedimentation velocity and sedimentation equilibrium in the analytical ultracentrifuge (SEDFIT, SEDFIT-MSTAR and MULTISIG analysis) showed that VanS in the absence of the ligand is almost entirely monomeric (molar mass M = 45.7 kDa) in dilute aqueous solution with a trace amount of high molar mass material (M ~ 200 kDa). The sedimentation coefficient s suggests the monomer adopts an extended conformation in aqueous solution with an equivalent aspect ratio of ~(12 ± 2). In the presence of vancomycin over a 33% increase in the sedimentation coefficient is observed with the appearance of additional higher s components, demonstrating an interaction, an observation consistent with our circular dichroism measurements. The two possible causes of this increase in s – either a ligand induced dimerization and/or compaction of the monomer are considered.

Citation

Phillips-Jones, M. K., Channell, G. A., Kelsall, C. J., Hughes, C. S., Ashcroft, A. E., Patching, S. G., Dinu, V., Gillis, R. B., Adams, G. G., & Harding, S. E. (2017). Hydrodynamics of the VanA-type VanS histidine kinase: an extended solution conformation and first evidence for interactions with vancomycin. Scientific Reports, 7(1), 1-12. https://doi.org/10.1038/srep46180

• Journal Article Type: Article
• Acceptance Date: Mar 10, 2017
• Online Publication Date: Apr 11, 2017
• Publication Date: 2017-12
• Deposit Date: Jun 20, 2017
• Publicly Available Date: Jun 20, 2017
• Journal: Scientific Reports
• Electronic ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 1
• Article Number: 46180
• Pages: 1-12
• DOI: https://doi.org/10.1038/srep46180
• Public URL: https://nottingham-repository.worktribe.com/output/855661
• Publisher URL: https://doi.org/10.1038/srep46180
• Contract Date: Jun 20, 2017