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The human cytomegalovirus UL44 C clamp wraps around DNA.

ABSTRACT: Processivity factors tether the catalytic subunits of DNA polymerases to DNA so that continuous synthesis of long DNA strands is possible. The human cytomegalovirus DNA polymerase subunit UL44 forms a C clamp-shaped dimer intermediate in structure between monomeric herpes simplex virus UL42, which binds DNA directly via a basic surface, and the trimeric sliding clamp PCNA, which encircles DNA. To investigate how UL44 interacts with DNA, calculations were performed in which a 12 bp DNA oligonucleotide was docked to UL44. The calculations suggested that UL44 encircles DNA, which interacts with basic residues both within the cavity of the C clamp and in flexible loops of UL44 that complete the "circle." The results of mutational and crosslinking studies were consistent with this model. Thus, UL44 is a "hybrid" of UL42 and PCNA: its structure is intermediate between the two and its mode of interaction with DNA has elements of both.

SUBMITTER: Komazin-Meredith G

PROVIDER: S-EPMC2878485 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature

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The human cytomegalovirus UL44 C clamp wraps around DNA.

Komazin-Meredith Gloria G Petrella Robert J RJ Santos Webster L WL Filman David J DJ Hogle James M JM Verdine Gregory L GL Karplus Martin M Coen Donald M DM

Structure (London, England : 1993) 20080801 8

Processivity factors tether the catalytic subunits of DNA polymerases to DNA so that continuous synthesis of long DNA strands is possible. The human cytomegalovirus DNA polymerase subunit UL44 forms a C clamp-shaped dimer intermediate in structure between monomeric herpes simplex virus UL42, which binds DNA directly via a basic surface, and the trimeric sliding clamp PCNA, which encircles DNA. To investigate how UL44 interacts with DNA, calculations were performed in which a 12 bp DNA oligonucle ...[more]

PMID: 18682223

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