Crystal structure of the conserved core of the herpes simplex virus transcriptional regulatory protein VP16

On infection, the herpes simplex virus (HSV) virion protein VP16 (Vmw65; al pha TIF) forms a transcriptional regulatory complex-the VP16-induced comple x-with two cellular proteins, HCF and Oct-1, on VP16-responsive cis-regulat ory elements in HSV immediate-early promoters called TAATGARAT, Comparison of different HSV VP16 sequences reveals a conserved core region that is suf ficient for VP16-induced complex formation. The crystal structure of the VP 16 core has been determined at 2.1 Angstrom resolution. The results reveal a novel, seat-like protein structure. Together with the activity of mutant VP16 proteins, the structure of Gee VP16 suggests that it contains (1) a di sordered carboxy-terminal region that associates with HCF, Oct-1, and DNA i n the VP16-induced complex, and (2) a structured region involved in virion assembly and possessing a novel DNA-binding surface that differentiates amo ng TAATGARAT VP16-response elements.