Common sialylated glycan in Actinobacillus suis

A sialylated oligosaccharide was identified in four representative strains of the Gram-negative swine pathogen, Actinobacillus suis. As characterized, the glycan consists of a free oligosaccharide with a N-acetyl-lactosamine-like backbone decorated with sialic acid, phosphoethanolamine (PEA) and O-acetyl units: 9-O-Ac-Neu5Ac-(2 -> 6)-beta-d-Galp-(1 -> 4)-beta-d-6-O-Ac-GlcpNAc-(1 -> 3)-[PEA -> 6]-beta-d-Galp-(1 -> 3)-beta-d-GlcpNAc-(1 -> 2)-[9-O-Ac-Neu5Ac-(2 -> 6)]-beta-d-Galp-(1 -> 4)-beta-d-6-O-Ac-GlcpNAc-(1 -> 3)-[PEA -> 6]-beta-d-Galp-(1 -> 3)-d-GlcpNAc. The ubiquitous expression of this sialylated glycan suggests that this carbohydrate may play an important role in the survival of A. suis in the host.