HMM Summary Page: TIGR03022

Functionundecaprenyl-phosphate galactose phosphotransferase WbaP
Gene SymbolwbaP
Trusted Cutoff403.00
Domain Trusted Cutoff403.00
Noise Cutoff308.55
Domain Noise Cutoff308.55
Isology Typesubfamily
EC Number2.7.8.6
HMM Length456
AuthorSelengut J
Entry DateJul 27 2006 10:55AM
Last ModifiedMar 1 2011 11:50AM
CommentThe WbaP (formerly RfbP) protein has been characterized [1,2] as the first enzyme in O-antigen biosynthesis in Salmonella typhimurium. The enzyme transfers galactose from UDP-galactose to a polyprenyl carrier (utilizing the highly conserved C-terminal sugar transferase domain, PF02397) a reaction which takes place at the cytoplasmic face of the inner membrane. The N-terminal hydrophobic domain is then believed to facilitate the "flippase" function of transferring the liposaccharide unit from the cytoplasmic face to the periplasmic face of the inner membrane. This model includes the enterobacterial enzymes, where the function is presumed to be identical to the S. typhimurium enzyme as well as a somewhat broader group which are likely to catalyze the same or highly similar reactions based on a phylogenetic tree-building analysis of the broader sugar transferase family. Most of these genes are found within large operons dedicated to the production of complex exopolysaccharides such as the enterobacterial O-antigen. The most likely heterogeneity would be in the precise nature of the sugar molecule transferred.
ReferencesRN [1] RM PMID: 8626328 RT C-terminal half of Salmonella enterica WbaP (RfbP) is the galactosyl-1-phosphate transferase domain catalyzing the first step of O-antigen synthesis. RA Wang L, Liu D, Reeves PR RL J Bacteriol. 1996 May;178(9):2598-604. RN [2] RM PMID: 12324313 RT Functional expression of enterobacterial O-polysaccharide biosynthesis enzymes in Bacillus subtilis. RA Schaffer C, Wugeditsch T, Messner P, Whitfield C. RL Appl Environ Microbiol. 2002 Oct;68(10):4722-30.