7LGR

Streptococcus mutans Collagen binding Protein CNM - N2 Domain

Summary for 7LGR

• Entry DOI: 10.2210/pdb7lgr/pdb
• Descriptor: Collagen-binding adhesin (2 entities in total)
• Functional Keywords: streptococcus mutans, cnm, c-terminal n2 domain, cell adhesion, collagen binding
• Biological source: Streptococcus mutans
• Total number of polymer chains: 1
• Total formula weight: 19724.16

Authors

Schormann, N.,Deivanayagam, C. (deposition date: 2021-01-20, release date: 2022-01-26, Last modification date: 2026-09-09)

Primary citation

Mieher, J.L.,Schormann, N.,Wu, R.,Patel, M.,Purushotham, S.,Lemos, J.,Abranches, J.,Wu, H.,Deivanayagam, C.
Streptococcus mutans Collagen-Binding Protein Cnm Is a Multifunctional Adhesin: A Structural Investigation.
Mol Oral Microbiol, 40:265-277, 2025

PubMed Abstract: The collagen-binding adhesin Cnm is a known virulence factor of Streptococcus mutans. It is present in specific serotypes (mostly e, f, and k strains) of S. mutans and belongs to the LPXTG family of cell wall-anchored surface adhesins. Here, we report the crystal structure of the collagen-binding N domain of S. mutans Cnm. Using the Staphylococcus aureus collagen-binding protein Cna, which shares high sequence and structural homology with Cnm, we modeled collagen binding to S. mutans Cnm. The comparative analysis identified three conserved collagen-binding residues (Y176, F192, N194) and four equivalent residues that are different in their composition (D224, T226, S232, M276). This study also discovered the multifunctional attributes of this protein, where Cnm-FL, Cnm-N and the individual domains of Cnm-N and Cnm-N adhere with high affinity to the scavenger receptor cysteine-rich (SRCR) domains of glycoprotein 340 (Gp340). Protein-protein docking of Cnm-N and SRCR showed the possibility of a shared binding site at the collagen-binding interface of Cnm-N. Furthermore, competition experiments using collagen and SRCR with Cnm-N, Cnm-N and Cnm-FL constructs confirmed that collagen and SRCR share a binding site. Subsequent alanine substitution mutagenesis of the predicted collagen-binding residues validated our modeling results, confirming that Y176 and F192 are important residues for collagen and SRCR/Gp340 binding.

PubMed: 40862507
DOI: 10.1111/omi.70005

Experimental method

X-RAY DIFFRACTION (1.6 Å)