The enzyme is involved in the biosynthesis of the polymannose O-polysaccharide in the outer leaflet of the membrane of Escherichia coli serotype O9a. O-Polysaccharide structures vary extensively because of differences in the number and type of sugars in the repeat unit. The dual kinase/methylase WbdD also catalyses the preceding phosphorylation of ¦Á-D-Man-(1¡ú2)-¦Á-D-Man-(1¡ú2)-[¦Á-D-Man-(1¡ú3)-¦Á-D-Man-(1¡ú3)-¦Á-D-Man-(1¡ú2)-¦Á-D-Man-(1¡ú2)]N-¦Á-D-Man-(1¡ú3)-¦Á-D-Man-(1¡ú3)-¦Á-D-Man-(1¡ú3)-¦Á-D-GlcNAc-diphospho-ditrans,octacis-undecaprenol (cf. EC 2.7.1.181, polymannosyl GlcNAc-diphospho-ditrans,octacis-undecaprenol kinase).
