This is the DNA-binding domain (DBD) of Papillomavirus E1 protein, a DNA helicase that is required for initiation of viral DNA replication. This protein forms a complex with the E2 protein Pfam:PF00508 at the origin of replication (ori) [1,2]. This domain is found in the central region of E1 and binds DNA at specific sites of viral origin, and also binds cooperatively with E2-DBD. This domain comprises a five-stranded antiparallel beta-sheet flanked by alpha helices on each side [2]. This domain binds originally as a dimer in which each monomer binds to one half-site of the palindromic E1 binding site, and promotes the assembly of the hexameric helicase on the ori [2]. E1 has a domain architecture and function similar to SV40 T-antigen [1].

1: The X-ray structure of the papillomavirus helicase in complex with its molecular matchmaker E2. Abbate EA, Berger JM, Botchan MR; Genes Dev. 2004;18:1981-1996. PMID:15289463

2: Crystal structure of the DNA binding domain of the replication initiation protein E1 from papillomavirus. Enemark EJ, Chen G, Vaughn DE, Stenlund A, Joshua-Tor L; Mol Cell. 2000;6:149-158. PMID:10949036