This is the C-terminal domain found in Wza, an integral outer membrane lipoprotein, which is essential for group 1 capsule export in Escherichia coli. The domain is exposed on the cell surface and is suggested to mimic antimicrobial peptide pore formation [1].

1: Wza the translocon for E. coli capsular polysaccharides defines a new class of membrane protein. Dong C, Beis K, Nesper J, Brunkan-Lamontagne AL, Clarke BR, Whitfield C, Naismith JH; Nature. 2006;444:226-229. PMID:17086202