Protein Family Models

Date:

2024-08-14

This Pfam family represents a conserved region from a number of different bacterial sugar transferases, involved in diverse biosynthesis pathways. [1]. 9423846. Identification of a genetic locus essential for serotype. b-specific antigen synthesis in Actinobacillus. actinomycetemcomitans.. Yoshida Y, Nakano Y, Yamashita Y, Koga T;. Infect Immun 1998;66:107-114. (from Pfam)

Date:

2024-08-14

sugar transferase similar to Xanthomonas campestris UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase that catalyzes the transfer of the glucose-1-phosphate moiety from UDP-Glc onto the carrier lipid undecaprenyl phosphate (C55-P), forming a phosphoanhydride bond yielding to glucosyl-pyrophosphoryl-undecaprenol (Glc-PP-C55)

Date:

2017-02-24

Members of this family are generally found near other genes involved in the biosynthesis of a variety of exopolysaccharides. These proteins consist of two fused domains, an N-terminal hydrophobic domain of generally low conservation and a highly conserved C-terminal sugar transferase domain (PF02397). Characterized and partially characterized members of this subfamily include Salmonella WbaP (originally RfbP) [1], E. coli WcaJ [2], Methylobacillus EpsB [3], Xanthomonas GumD [4], Vibrio CpsA [5], Erwinia AmsG [6], Group B Streptococcus CpsE (originally CpsD) [7], and Streptococcus suis Cps2E [8]. Each of these is believed to act in transferring the sugar from, for instance, UDP-glucose or UDP-galactose, to a lipid carrier such as undecaprenyl phosphate as the first (priming) step in the synthesis of an oligosaccharide "block". This function is encoded in the C-terminal domain. The liposaccharide is believed to be subsequently transferred through a "flippase" function from the cytoplasmic to the periplasmic face of the inner membrane by the N-terminal domain. Certain closely related transferase enzymes such as Sinorhizobium ExoY [9] and Lactococcus EpsD [10] lack the N-terminal domain and are not found by this model.

Date:

2021-08-23

This 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].

Date:

2023-06-23