2py5: Difference between revisions

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.

Structures of phi29 DNA polymerase complexed with substrate: the mechanism of translocation in B-family polymerases., Berman AJ, Kamtekar S, Goodman JL, Lazaro JM, de Vega M, Blanco L, Salas M, Steitz TA, EMBO J. 2007 Jul 25;26(14):3494-505. Epub 2007 Jul 5. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17611604 17611604]

[[Category: Berman, A J.]]

[[Category: Goodman, J L.]]

[[Category: Lazaro, J M.]]

[[Category: Steitz, T A.]]

[[Category: Vega, M de.]]

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