Many bacteria are covered in a layer of surface-associated polysaccharide called the capsule. These capsules can be divided into four groups depending upon the organisation of genes responsible for capsule assembly, the assembly pathway and regulation.

This superfamily includes the capsule assembly protein Wzi, an 18-stranded beta-barrel with a periplasmic helical bundle that has a role in the recognition of the capsular polysaccharide. It is predicted that the Wzi-polysaccharide interaction is critical in the initialisation step of the functional capsule biosynthesis and teh later steps of the capsule assembly.

PFAM:PF14052,DOI:10.1016/j.str.2013.03.010