Herpes Simplex Virus Processivity Factor UL42 Imparts Increased DNA-Binding Specificity to the Viral DNA Polymerase and Decreased Dissociation from Primer-Template without Reducing the Elongation Rate

• DOI: 10.1128/jvi.73.1.55-66.1999
• Publication Date: 2019-12-31T18:18:13Z
• Authors: Klaus Weisshart; Connie S. Chow; Donald M. Coen
• Keywords: Processivity; Primer (cosmetics); DNA polymerase II; DNA clamp; DNA polymerase delta

ABSTRACT Herpes simplex virus DNA polymerase consists of a catalytic subunit, Pol, and processivity UL42, that, unlike other established factors, binds directly. We used gel retardation filter-binding assays to investigate how UL42 affects the polymerase-DNA interaction. The Pol/UL42 heterodimer bound more tightly in primer-template configuration than single-stranded (ssDNA), while Pol alone ssDNA configuration. affinity for was reduced severalfold relative that increased ∼15-fold Pol. circular double-stranded (dsDNA) drastically but short primer-templates modestly UL42. associated with ∼2-fold faster did dissociated ∼10-fold slowly, resulting half-life 2 h subnanomolar K d . Despite such stable binding, rapid-quench analysis revealed rates elongation were essentially same, ∼30 nucleotides/s. Taken together, these studies indicate (i) is likely its subunits associate rather nonspecifically either or dsDNA, (ii) reduces rate dissociation from not elongation. Two models interactions during replication may explain findings are presented.