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)-β-DGalp-(1→4)-β-D-6-O-Ac-GlcpNAc-(1→3)-[PEA→6]-βD-Galp-(1→3)-β-D-GlcpNAc-(1→2)-[9-O-Ac-Neu5Ac(2→6)]-β-D-Galp-(1→4)-β-D-6-O-Ac-GlcpNAc-(1→3)[PEA→6]-β-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.