This domain appears to be a zinc finger. The alignment shows four conserved cysteine residues and a conserved tryptophan. It was first identified by [1], and is predicted to be a "highly specialised mononuclear four-cysteine zinc finger...that plays a role in DNA binding and/or promoting protein-protein interactions in complicated eukaryotic processes including ...chromatin methylation status and early embryonic development." Weak homology to Pfam:PF00628 further evidences these predictions (personal obs: C Yeats). Twelve different CW-domain-containing protein subfamilies are described, with different subfamilies being characteristic of vertebrates, higher plants and other animals in which these domain is found [1].

1: The CW domain, a structural module shared amongst vertebrates, vertebrate-infecting parasites and higher plants. Perry J, Zhao Y; Trends Biochem Sci 2003;28:576-580. PMID:14607086