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EMBO J. 2007 Jul 25;26(14):3494-505. Epub 2007 Jul 5.

Structures of phi29 DNA polymerase complexed with substrate: the mechanism of translocation in B-family polymerases.

Author information

1
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.

Abstract

Replicative DNA polymerases (DNAPs) move along template DNA in a processive manner. The structural basis of the mechanism of translocation has been better studied in the A-family of polymerases than in the B-family of replicative polymerases. To address this issue, we have determined the X-ray crystal structures of phi29 DNAP, a member of the protein-primed subgroup of the B-family of polymerases, complexed with primer-template DNA in the presence or absence of the incoming nucleoside triphosphate, the pre- and post-translocated states, respectively. Comparison of these structures reveals a mechanism of translocation that appears to be facilitated by the coordinated movement of two conserved tyrosine residues into the insertion site. This differs from the mechanism employed by the A-family polymerases, in which a conserved tyrosine moves into the templating and insertion sites during the translocation step. Polymerases from the two families also interact with downstream single-stranded template DNA in very different ways.

PMID:
17611604
PMCID:
PMC1933411
DOI:
10.1038/sj.emboj.7601780
[Indexed for MEDLINE]
Free PMC Article

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