1T6L

Crystal Structure of the Human Cytomegalovirus DNA Polymerase Subunit, UL44

Summary for 1T6L

• Entry DOI: 10.2210/pdb1t6l/pdb
• Descriptor: DNA polymerase processivity factor (2 entities in total)
• Functional Keywords: processivity fold, replication
• Biological source: Human herpesvirus 5 (Human cytomegalovirus)
• Cellular location: Virion: P16790
• Total number of polymer chains: 1
• Total formula weight: 32576.51

Authors

Appleton, B.A.,Loregian, A.,Filman, D.J.,Coen, D.M.,Hogle, J.M. (deposition date: 2004-05-06, release date: 2004-08-10, Last modification date: 2024-02-14)

Primary citation

Appleton, B.A.,Loregian, A.,Filman, D.J.,Coen, D.M.,Hogle, J.M.
The Cytomegalovirus DNA Polymerase Subunit UL44 Forms a C Clamp-Shaped Dimer.
Mol.Cell, 15:233-244, 2004

PubMed Abstract: 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.

PubMed: 15260974
DOI: 10.1016/j.molcel.2004.06.018

Experimental method

X-RAY DIFFRACTION (1.85 Å)