1t6l: Difference between revisions

[[Image:1t6l.jpg|left|200px]]<br /><applet load="1t6l" size="350" color="white" frame="true" align="right" spinBox="true"  

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.

1T6L is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Human_herpesvirus_5 Human herpesvirus 5]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1T6L OCA].  

[[Category: Appleton, B A.]]

[[Category: Coen, D M.]]

[[Category: Filman, D J.]]

[[Category: Hogle, J M.]]

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