Sialyltransferases Obtained from Marine Bacteria

Abstract

Sialyltransferases transfer N-acetylneuraminic acid (Neu5Ac) from cytidine monophosphate N-acetylneuraminic acid (CMP-Neu5Ac) to the acceptor substrate. Up to the present, many sialyltransferases have been cloned from mammalian and bacterial sources. All the sialyltransferases have been classified into five families in the CAZy (carbohydrate-active enzymes) database (families 29, 38, 42, 52 and 80), and all of the marine bacterial sialyltransferases are classified into the family 80. During the course of our study, we have isolated several marine bacteria producing sialyltransferases. Many of them were identified as the bacteria which were classified into genera Photobacterium and Vibrio. Furthermore, we have also demonstrated that these marine bacterial sialyltransferases have unique acceptor substrate specificity, compared with those of mammalian sialyltransferases. N-Acetylneuraminic acid is usually linked to the terminal position of glycan moiety of glycoconjugates, including glycoprotein and glycolipid. Enzymatic sialylation using sialyltransferase is a single-step process with high positional and anomer selectivity and high reaction yield under mild reaction conditions. Therefore, sialyltransferase is believed to be one of the most important enzymes in the field of glycotechnology and to be a powerful tool for the study of glycobiology.