Enzymatic synthesis of unique sialyloligosaccharides using marine bacterial α-(2→3)- and α-(2→6)-sialyltransferases

We investigated the acceptor substrate specificities of marine bacterial α-(2→3)-sialyltransferase cloned from Photobacterium sp. JT-ISH-224 and α-(2→6)-sialyltransferase cloned from Photobacterium damselae JT0160 using several saccharides as acceptor substrates. After purifying the enzymatic reaction products, we confirmed their structure by NMR spectroscopy. The α-(2→3)-sialyltransferase transferred N-acetylneuraminic acid (Neu5Ac) from cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac) to the β-anomeric hydroxyl groups of mannose (Man) and α-Manp-(1→6)-Manp, and α-(2→6)-sialyltransferase transferred N-acetylneuraminic acid to the 6-OH groups of the non-reducing end galactose residues in β-Galp-(1→3)-GlcpNAc and β-Galp-(1→6)-GlcpNAc.

Enzymatic reaction product derived from α-Manp-(1→6)-Manp as an acceptor substrate by marine bacterial sialyltransferase.Figure optionsDownload as PowerPoint slide