This domain is found at the C-terminus of the Wzt protein [1]. The crystal structure of C-Wzt(O9a) reveals a beta sandwich with an immunoglobulin-like topology that contains the O-antigenic polysaccharide binding pocket. This domain is often associated with the ABC-transporter domain.

1: Substrate binding by a bacterial ABC transporter involved in polysaccharide export. Cuthbertson L, Kimber MS, Whitfield C; Proc Natl Acad Sci U S A. 2007;104:19529-19534. PMID:18032609