This domain is found in 1 to 3 tandem copies in a wide variety of bacterial cell surface proteins. It has been show the three tandem repeats of the CWB2 domain are essential for correct anchoring to the cell wall [1]. It was shown that in SlpA and Cwp2 that these domains were essential for the binding of PSII an anionic teichoic acid-like component of the cell wall [1]. The structure of the Cwp8 and Cwp6 proteins shows that this domain forms a trimeric arrangement with each domain adopting a structure with some similarity to the Toprim fold [2]. A groove containing many conserved residues was predicted to be the site of the PSII molecule [2].

1: Clostridium difficile surface proteins are anchored to the cell wall using CWB2 motifs that recognise the anionic polymer PSII. Willing SE, Candela T, Shaw HA, Seager Z, Mesnage S, Fagan RP, Fairweather NF; Mol Microbiol. 2015;96:596-608. PMID:25649385

2: The CWB2 Cell Wall-Anchoring Module Is Revealed by the Crystal Structures of the\tClostridium difficile Cell Wall Proteins Cwp8 and Cwp6. Usenik A, Renko M, Mihelic M, Lindic N, Borisek J, Perdih A, Pretnar G, Muller U, Turk D; Structure. 2017;25:514-521. PMID:28132783