Members of this family adopt a structure consisting of four alpha helices, arranged in an array. They bind specifically and directly to the xeroderma pigmentosum group C protein (XPC) to initiate nucleotide excision repair [1].

1: Solution structure and backbone dynamics of the XPC-binding domain of the human DNA repair protein hHR23B. Kim B, Ryu KS, Kim HJ, Cho SJ, Choi BS; FEBS J. 2005;272:2467-2476. PMID:15885096