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Rivière G, Peng EQ, Brotgandel A, Andring JT, Lakshmanan RV, Agbandje-McKenna M, McKenna R, Brady LJ, Long JR. Characterization of an intermolecular quaternary interaction between discrete segments of the Streptococcus mutans adhesin P1 by NMR spectroscopy. FEBS J 2019; 287:2597-2611. [PMID: 31782893 DOI: 10.1111/febs.15158] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/13/2019] [Accepted: 11/27/2019] [Indexed: 11/30/2022]
Abstract
Cell surface-localized P1 adhesin (aka Antigen I/II or PAc) of the cariogenic bacterium Streptococcus mutans mediates sucrose-independent adhesion to tooth surfaces. Previous studies showed that P1's C-terminal segment (C123, AgII) is also liberated as a separate polypeptide, contributes to cellular adhesion, interacts specifically with intact P1 on the cell surface, and forms amyloid fibrils. Identifying how C123 specifically interacts with P1 at the atomic level is essential for understanding related virulence properties of S. mutans. However, with sizes of ~ 51 and ~ 185 kDa, respectively, C123 and full-length P1 are too large to achieve high-resolution data for full structural analysis by NMR. Here, we report on biologically relevant interactions of the individual C3 domain with A3VP1, a polypeptide that represents the apical head of P1 as it is projected on the cell surface. Also evaluated are C3's interaction with C12 and the adhesion-inhibiting monoclonal antibody (MAb) 6-8C. NMR titration experiments with 15 N-enriched C3 demonstrate its specific binding to A3VP1. Based on resolved C3 assignments, two binding sites, proximal and distal, are identified. Complementary NMR titration of A3VP1 with a C3/C12 complex suggests that binding of A3VP1 occurs on the distal C3 binding site, while the proximal site is occupied by C12. The MAb 6-8C binding interface to C3 overlaps with that of A3VP1 at the distal site. Together, these results identify a specific C3-A3VP1 interaction that serves as a foundation for understanding the interaction of C123 with P1 on the bacterial surface and the related biological processes that stem from this interaction. DATABASE: BMRB submission code: 27935.
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Affiliation(s)
- Gwladys Rivière
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA.,National High Magnetic Field Laboratory, University of Florida, Gainesville, FL, USA
| | - Emily-Qingqing Peng
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Albert Brotgandel
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jacob T Andring
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Renuk V Lakshmanan
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - L Jeannine Brady
- College of Dentistry, Department of Oral Biology, University of Florida, Gainesville, FL, USA
| | - Joanna R Long
- Department of Biochemistry and Molecular Biology and McKnight Brain Institute, University of Florida, Gainesville, FL, USA.,National High Magnetic Field Laboratory, University of Florida, Gainesville, FL, USA
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