2WQS

Crystal structure of the C-terminal domain of Streptococcus gordonii surface protein SspB

Summary for 2WQS

• Entry DOI: 10.2210/pdb2wqs/pdb
• Related: 2WD6 2WOY 2WZA
• Descriptor: AGGLUTININ RECEPTOR, CALCIUM ION, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: cell adhesion, cell wall, antigen i/ii, peptidoglycan-anchor
• Biological source: STREPTOCOCCUS GORDONII
• Cellular location: Secreted, cell wall; Peptidoglycan-anchor (Potential): P16952
• Total number of polymer chains: 1
• Total formula weight: 39896.19

Authors

Forsgren, N.,Persson, K. (deposition date: 2009-08-27, release date: 2010-02-16, Last modification date: 2023-12-20)

Primary citation

Forsgren, N.,Lamont, R.J.,Persson, K.
Two Intramolecular Isopeptide Bonds are Identified in the Crystal Structure of the Streptococcus Gordonii Sspb C-Terminal Domain.
J.Mol.Biol., 397:740-, 2010

PubMed Abstract: Streptococcus gordonii is a primary colonizer and is involved in the formation of dental plaque. This bacterium expresses several surface proteins. One of them is the adhesin SspB, which is a member of the Antigen I/II family of proteins. SspB is a large multi-domain protein that has interactions with surface molecules on other bacteria and on host cells, and is thus a key factor in the formation of biofilms. Here, we report the crystal structure of a truncated form of the SspB C-terminal domain, solved by single-wavelength anomalous dispersion to 1.5 A resolution. The structure represents the first of a C-terminal domain from a streptococcal Antigen I/II protein and is comprised of two structurally related beta-sandwich domains, C2 and C3, both with a Ca(2+) bound in equivalent positions. In each of the domains, a covalent isopeptide bond is observed between a lysine and an asparagine, a feature that is believed to be a common stabilization mechanism in Gram-positive surface proteins. S. gordonii biofilms contain attachment sites for the periodontal pathogen Porphyromonas gingivalis and the SspB C-terminal domain has been shown to have one such recognition motif, the SspB adherence region. The motif protrudes from the protein, and serves as a handle for attachment. The structure suggests several additional putative binding surfaces, and other binding clefts may be created when the full-length protein is folded.

PubMed: 20138058
DOI: 10.1016/J.JMB.2010.01.065

Experimental method

X-RAY DIFFRACTION (1.7 Å)