Synthase-dependent exopolysaccharide secretion in Gram-negative bacteria

• Published in: Trends in microbiology (Regular ed.) 2013-02, Vol.21 (2), p.63-72
• Main Authors: Whitney, J.C, Howell, P.L
• Format: Article
• Language: English
• Subjects: alginate; Alginates; Bacterial Proteins - metabolism; Bacterial Secretion Systems - physiology; beta-Glucans - metabolism; biosynthesis; cellulose; Cellulose - biosynthesis; exopolysaccharide; exopolysaccharides; Glucuronic Acid - biosynthesis; Gram-negative bacteria; Gram-Negative Bacteria - metabolism; guanosine monophosphate; Hexuronic Acids; Internal Medicine; poly-β-d-N-acetylglucosamine; Polysaccharides, Bacterial - biosynthesis; Polysaccharides, Bacterial - secretion; porins; scaffolding proteins; secretion; synthase
• ISSN: 0966-842X; 1878-4380
• DOI: 10.1016/j.tim.2012.10.001

The biosynthesis and export of bacterial cell-surface polysaccharides is known to occur through several distinct mechanisms. Recent advances in the biochemistry and structural biology of several proteins in synthase-dependent polysaccharide secretion systems have identified key conserved components of this pathway in Gram-negative bacteria. These components include an inner-membrane-embedded polysaccharide synthase, a periplasmic tetratricopeptide repeat (TPR)-containing scaffold protein, and an outer-membrane β-barrel porin. There is also increasing evidence that many synthase-dependent systems are post-translationally regulated by the bacterial second messenger bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP). Here, we compare these core proteins in the context of the alginate, cellulose, and poly-β-d-N-acetylglucosamine (PNAG) secretion systems.