Isolation and structure elucidation of GM4-type gangliosides from the Okinawan starfish Protoreaster nodosus

Abstract

Three new ganglioside molecular species, termed PNG-1, PNG-2A, and PNG-2B were isolated from pyloric caeca of the starfish Protoreaster nodosus. Their structures were elucidated using a combination of spectroscopic and chemical methods, and characterized as 1-O-[8-O-methyl-N-acetyl-α-neuraminosyl- (2→3)-β-galactopyranosyl]-ceramide for PNG-1, 1-O-[β- galactofuranosyl-(1→3)-α-galactopyranosyl-(1→4) -8-O-methyl-N-acetyl-α-neuraminosyl-(2→3)-β-galactopyranosyl] -ceramide for PNG-2A, and 1-O-[β-galacto furanosyl-(1→3)-α- galactopyranosyl-(1→9)-N-acetyl-α-neuraminosyl-(2→3) -β-galactopyr anosyl]-ceramide for PNG-2B. PNG-2A and PNG-2B represent the first GM4 elongation products in nature. © 2012 by the authors; licensee MDPI.