Helicase-DNA polymerase interaction is critical to initiate leading-strand DNA synthesis.
Article Details
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Zhang H, Lee SJ, Zhu B, Tran NQ, Tabor S, Richardson CC
Helicase-DNA polymerase interaction is critical to initiate leading-strand DNA synthesis.
Proc Natl Acad Sci U S A. 2011 Jun 7;108(23):9372-7. doi: 10.1073/pnas.1106678108. Epub 2011 May 23.
- PubMed ID
- 21606333 [ View in PubMed]
- Abstract
Interactions between gene 4 helicase and gene 5 DNA polymerase (gp5) are crucial for leading-strand DNA synthesis mediated by the replisome of bacteriophage T7. Interactions between the two proteins that assure high processivity are known but the interactions essential to initiate the leading-strand DNA synthesis remain unidentified. Replacement of solution-exposed basic residues (K587, K589, R590, and R591) located on the front surface of gp5 with neutral asparagines abolishes the ability of gp5 and the helicase to mediate strand-displacement synthesis. This front basic patch in gp5 contributes to physical interactions with the acidic C-terminal tail of the helicase. Nonetheless, the altered polymerase is able to replace gp5 and continue ongoing strand-displacement synthesis. The results suggest that the interaction between the C-terminal tail of the helicase and the basic patch of gp5 is critical for initiation of strand-displacement synthesis. Multiple interactions of T7 DNA polymerase and helicase coordinate replisome movement.