Presence and location of an O-acetyl group in O4-antigen of Vibrio parahaemolyticus.

A polysaccharide moiety (PS) released from O4-LPS of Vibrio parahaemolyticus was purified. The constituent sugars of the purified PS were glucose, galactose, arabinose, fucose, heptose, N-acetyl galactosamine and an unknown N-acetyl amino sugar. The unknown amino sugar was deduced to be a terminal deoxy amino sugar from its NMR spectrum. PNMR spectroscopy at 200 MHz, periodate oxidation and treatment with alpha-L-fucosidase of the purified PS sample before and after alcoholic sodium methoxide-treatment suggested that PS contained an O-acetyl and alpha-linked non-reducing terminal L-fucose and that the O-acetyl group was located at the C-2 or C-4 position of the non-reducing terminal fucose. The contribution of the O-acetyl group located in L-fucose to the O4-antigenic determinant seemed to be small, judging from immunochemical experiments.