6cam

Publication Abstract from PubMed

The high-resolution structure of Glucan binding protein C (GbpC) at 1.14 A, a sucrose-dependent virulence factor of the dental caries pathogen Streptococcus mutans, has been determined. GbpC not only shares structural similarities with the V-regions of AgI/II and SspB, but also functional adherence to SAG and its scavenger receptor cysteine rich domains (SRCRs) which is not only a newly identified function for GbpC, but also an additional fail-safe binding mechanism for S. mutans Despite the structural similarities with S. mutans Antigen I/II (AgI/II) and SspB of Streptococcus gordonii, GbpC remains unique among these surface proteins in its propensity to adhere to dextran/glucans. The complex crystal structure of GbpC with dextrose (beta-D glucose, BGC) highlights exclusive structural features that facilitates this interaction with dextran. Targeted deletion mutant studies on GbpC's divergent loop region in the vicinity of a highly-conserved calcium binding site confirm its role in biofilm formation. Finally, we present a model for adherence to dextran. The structure of GbpC highlights how artfully microbes have engineered the lectin-like folds to broaden their functional adherence repertoire.

Glucan Binding Protein C of Streptococcus mutans Mediates both Sucrose-Independent and Sucrose-Dependent Adherence.,Mieher JL, Larson MR, Schormann N, Purushotham S, Wu R, Rajashankar KR, Wu H, Deivanayagam C Infect Immun. 2018 Apr 23. pii: IAI.00146-18. doi: 10.1128/IAI.00146-18. PMID:29685986^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.