HMM Summary Page: TIGR03023

Functionundecaprenyl-phosphate glucose phosphotransferase
Trusted Cutoff410.75
Domain Trusted Cutoff410.75
Noise Cutoff364.25
Domain Noise Cutoff364.25
Isology Typeequivalog
EC Number2.7.8.-
HMM Length453
AuthorSelengut J
Entry DateJul 27 2006 12:46PM
Last ModifiedFeb 14 2011 3:27PM
CommentThis family of proteins encompasses the E. coli WcaJ protein involved in colanic acid biosynthesis [1], the Methylobacillus EpsB protein involved in methanolan biosynthesis [2], as well as the GumD protein involved in the biosynthesis of xanthan [3]. All of these are closely related to the well-characterized WbaP (formerly RfbP) protein [4] which is the first enzyme in O-antigen biosynthesis in Salmonella typhimurium. The enzyme transfers galactose from UDP-galactose (NOTE: not glucose) 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. Most of these genes are found within large operons dedicated to the production of complex exopolysaccharides such as the enterobacterial O-antigen. Colanic acid biosynthesis utilizes a glucose-undecaprenyl carrier [1], knockout of EpsB abolishes incorporation of UDP-glucose into the lipid phase [2] and the C-terminal portion of GumD has been shown to be responsible for the glucosyl-1-transferase activity [3].
ReferencesRN [1] RM PMID: 318640 RT Role of a sugar-lipid intermediate in colanic acid synthesis by Escherichia coli. RA Johnson JG, Wilson DB RL J Bacteriol. 1977 Jan;129(1):225-36. RN [2] RM 12624205 RA Yoshida T, Ayabe Y, Yasunaga M, Usami Y, Habe H, Nojiri H, Omori T RT Genes involved in the synthesis of the exopolysaccharide methanolan by the obligate methylotroph Methylobacillus sp strain 12S. RL Microbiology. 2003 Feb;149(Pt 2):431-44. RN [3] RM PMID: 9537354 RT Xanthomonas campestris pv. campestris gum mutants: effects on xanthan biosynthesis and plant virulence. RA Katzen F, Ferreiro DU, Oddo CG, Ielmini MV, Becker A, Puhler A, Ielpi L RL J Bacteriol. 1998 Apr;180(7):1607-17. RN [4] 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.
Genome PropertyGenProp0655: exopolysaccharide biosynthesis, exosortase B-associated (HMM-CLUST)
GenProp0931: colanic acid biosynthesis (HMM-CLUST)