Figure 1.

Schematic diagram of a single chain of polysialic acid composed of sialic monomers (orange circles) with α-2,8 keto-glycosidic linkages linked with a few β-linked poly-3-deoxy-d-manno-oct-2-ulosonic acid (KDO) linkers (green circle); a monomer structure is shown in the green box, anchored onto lyso-phosphatidylglycerol (lyso-PG), in the red circle; a lyso-PG structure is shown in the red box. The lyso-PG is surrounded with lipid A in the bacterial outer membrane (the O-antigens are omitted for clarity).