Structures of phi29 DNA polymerase complexed with substrate: the mechanism of translocation in B-family polymerasesBerman, A.J., Kamtekar, S., Goodman, J.L., Lazaro, J.M., de Vega, M., Blanco, L., Salas, M., Steitz, T.A.
(2007) EMBO J 26: 3494-3505
- PubMed: 17611604
- DOI: https://doi.org/10.1038/sj.emboj.7601780
- Primary Citation of Related Structures:
2PY5, 2PYJ, 2PYL, 2PZS
- PubMed 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.
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.