Microbial glycosyltransferases for carbohydrate synthesis: alpha-2,3-sialyltransferase from Neisseria gonorrheae

The alpha -2,3-sialyltransferase from Neisseria gonorrheae was overproduced in E. coli for exploitation of its substrate specificity and synthetic uti lity. Several potential acceptor substrates were synthesized in this study, including mono- and oligosaccharides, glycolipids, and glycopeptides and t heir sulfate derivatives. Some CMP-sialic acid derivatives with modificatio n at the C-5 position were also prepared for evaluation as donor substrates . It was found that the enzyme exhibits a broader acceptor substrate specif icity when compared to other sialyltransferases, though the donor specifici ty is quite limited. Application of the enzyme, to the preparative synthesi s of representative sialyl glycoconjugates has been demonstrated. On the ba sis of this work and the work of others, this enzyme is the most versatile and synthetically useful among all sialyltransferases known to date, especi ally for the synthesis of sulfate-containing glycoconjugates.