The polysialic acid-specific O-acetyltransferase OatC from Neisseria meningitidis serogroup C evolved apart from other bacterial sialate O-acetyltransferases.

Neisseria meningitidis serogroup C is a major cause of bacterial meningitis and septicaemia. This human pathogen is protected by a capsule composed of alpha2,9-linked polysialic acid that represents an important virulence factor. In the majority of strains, the capsular polysaccharide is modified by O-acetylation at C-7 or C-8 of the sialic acid residues.