The C terminal domain of CDC6 assumes a winged helix fold, with a five alpha-helical bundle (alpha15-alpha19) structure, backed on one side by three beta strands (beta6-beta8). It has been shown that this domain acts as a DNA-localisation factor, however its exact function is, as yet, unknown. Putative functions include: (1) mediation of protein-protein interactions and (2) regulation of nucleotide binding and hydrolysis. Mutagenesis studies have shown that this domain is essential for appropriate Cdc6 activity [1].

1: Structure and function of Cdc6/Cdc18: implications for origin recognition and checkpoint control. Liu J, Smith CL, DeRyckere D, DeAngelis K, Martin GS, Berger JM; Mol Cell. 2000;6:637-648. PMID:11030343