Structural highlights
Function
GUMK_XANCE Catalyzes the transfer of a glucuronic acid (GlcA) residue from UDP-glucuronate to mannose-alpha-1,3-glucose-beta-1,4-glucose-P-P-polyisoprenyl to form the lipid-linked tetrasaccharide GlcA-Man-Glc(2)-PP-Pol, with a glucuronic acid-beta-mannose linkage. Is involved in the biosynthesis of the exopolysaccharide xanthan, since it catalyzes the fourth glycosylation step in the assembly of the pentasaccharide-P-P-polyisoprenyl repeating unit of xanthan. Is unable to use the trisaccharide acceptor freed from the pyrophosphate lipid moiety. Does not show specificity for the lipidic portion of the acceptor. Shows diminished activity when tested with 6-O-acetyl-mannose-alpha-1,3-glucose-beta-1,4-glucose-P-P-polyisoprenyl, a putative intermediate in the synthesis of xanthan; this could indicate that acetylation of the internal mannose takes place after the formation of the GumK product.[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
References
- ↑ Barreras M, Abdian PL, Ielpi L. Functional characterization of GumK, a membrane-associated beta-glucuronosyltransferase from Xanthomonas campestris required for xanthan polysaccharide synthesis. Glycobiology. 2004 Mar;14(3):233-41. Epub 2004 Jan 21. PMID:14736729 doi:http://dx.doi.org/10.1093/glycob/cwh056
