Sequence of Escherichia coli O128 antigen biosynthesis cluster and functional identification of an α‐1,2‐fucosyltransferase

O128 is one of the most common atypical enteropathogenic Escherichia coli isolated from diarrhea patients worldwide. The primary structure of E. coli O128 repeat units has previously been determined as -->3)-beta-D-GalNAc-(1-->4)-alpha-D-Gal-(1-->3)-beta-D-GalNAc-(1-->6)-[alpha-L-Fuc-(1-->2)]-beta-D-Gal-(1--> pentasaccharide. Here we report the complete sequencing of E. coli O128 antigen biosynthesis gene cluster and its flanking regions. Comparative sequence analysis revealed the expected O128 antigen process genes, GDP-fucose biosynthesis genes and four potential glycosyltransferase genes responsible for the assembly of E. coli O128 antigen repeats. WbsJ was shown to encode an alpha-1,2-fucosyltransferase by enzymatic assays and nuclear magnetic resonance spectroscopy analysis.