1t6l | pdb_00001t6l
Crystal Structure of the Human Cytomegalovirus DNA Polymerase Subunit, UL44
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Overview
The human cytomegalovirus DNA polymerase consists of a catalytic subunit, UL54, and a presumed processivity factor, UL44. We have solved the crystal structure of residues 1-290 of UL44 to 1.85 A resolution by multiwavelength anomalous dispersion. The structure reveals a dimer of UL44 in the shape of a C clamp. Each monomer of UL44 shares its overall fold with other processivity factors, including herpes simplex virus UL42, which is a monomer that binds DNA directly, and the sliding clamp, PCNA, which is a trimer that surrounds DNA, although these proteins share no obvious sequence homology. Analytical ultracentrifugation and gel filtration measurements demonstrated that UL44 also forms a dimer in solution, and substitution of large hydrophobic residues along the homodimer interface with alanine disrupted dimerization and decreased DNA binding. UL44 represents a hybrid processivity factor as it binds DNA directly like UL42, but forms a C clamp that may surround DNA like PCNA.
About this Structure
1T6L is a Single protein structure of sequence from Human herpesvirus 5. Full crystallographic information is available from OCA.
Reference
The cytomegalovirus DNA polymerase subunit UL44 forms a C clamp-shaped dimer., Appleton BA, Loregian A, Filman DJ, Coen DM, Hogle JM, Mol Cell. 2004 Jul 23;15(2):233-44. PMID:15260974
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