April 1, 2006 Journal article Open Access

Identification of a sialate O-acetyltransferase from Campylobacter jejuni: Demonstration of direct transfer to the C-9 position of terminal α-2,8-linked sialic acid

Marie-France Karwaski; Michel Gilbert; Alex van Belkum; Jianjun Li; R. Scott Houliston; Harold C. Jarrell; Michiaki Koga; Hubert P. Endtz; Warren W. Wakarchuk; Nobuhiro Yuki

We have identified a sialate O-acetyltransferase in the lipo-oligosaccharide biosynthesis locus of Campylobacter jejuni. Strains possessing this locus are known to produce sialylated outer core structures that mimic host gangliosides, and have been implicated in triggering the onset of Guillain-Barre syndrome. The acetyltransferase, which was cloned and expressed as a fusion construct in Escherichia coli, is soluble and homologous with members of the NodL-LacA-CysE family of O-acetyltransferases. This enzyme catalyzes the transfer of O-acetyl groups onto oligosaccharide-bound sialic acid, with a high specificity for terminal α2,8-linked residues. The modification is directed to C-9 and not C-7 as is believed to occur more commonly in other organisms. Despite their wide prevalence and importance in both eukaryotes and prokaryotes, this is the first report to describe the characterization of a purified sialate O-acetyltransferase.