Abstract
Herpes simplex virus 1 encodes a protein that binds specifically to a viral DNA replication origin (oris). This origin-binding protein has been purified to homogeneity by means of sequence-specific DNA affinity chromatography. The purified origin-binding protein, which has a molecular weight of 83,000, interacts with both parts of the oris dyad; however, the affinity for the two sites differs by an order of magnitude. The sequence TTCGCA occurs as a nearly perfect direct repeat within the two sites and may constitute the recognition sequence for the origin-binding protein.