Abstract
Streptococcus mutans, the causative agent of human dental caries, expresses a cell wall attached Serotype c-specific Carbohydrate (SCC) that is critical for cell viability. SCC consists of a polyrhamnose backbone of →3)α-Rha(1 → 2)α-Rha(1→ repeats with glucose (Glc) side-chains and glycerol phosphate (GroP) decorations. This study reveals that SCC has one predominant and two more minor Glc modifications. The predominant Glc modification, α-Glc, attached to position 2 of 3-rhamnose, is installed by SccN and SccM glycosyltransferases and is the site of the GroP addition. The minor Glc modifications are β-Glc linked to position 4 of 3-rhamnose installed by SccP and SccQ glycosyltransferases, and α-Glc attached to position 4 of 2-rhamnose installed by SccN working in tandem with an unknown enzyme. Both the major and the minor β-Glc modifications control bacterial morphology, but only the GroP and major Glc modifications are critical for biofilm formation.
Document Type
Article
Publication Date
1-22-2025
Digital Object Identifier (DOI)
https://doi.org/10.1038/s41467-025-56205-1
Repository Citation
Rush, Jeffrey S.; Zamakhaeva, Svetlana; Murner, Nicholas R; Deng, Pan; Morris, Andrew J; Kenner, Cameron W; Black, Ian; Heiss, Christian; Azadi, Parastoo; Korotkov, Konstantin V; Widmalm, Göran; and Korotkova, Natalia, "Structure and mechanism of biosynthesis of Streptococcus mutans cell wall polysaccharide." (2025). Molecular and Cellular Biochemistry Faculty Publications. 198.
https://uknowledge.uky.edu/biochem_facpub/198
Notes/Citation Information
Nat Commun. 2025 Jan 22;16(1):954