Prechemistry nucleotide selection checkpoints in the reaction pathway of DNA polymerase I and roles of glu710 and tyr766.

ABSTRACT: The accuracy of high-fidelity DNA polymerases such as DNA polymerase I (Klenow fragment) is governed by conformational changes early in the reaction pathway that serve as fidelity checkpoints, identifying inappropriate template-nucleotide pairings. The fingers-closing transition (detected by a fluorescence resonance energy transfer-based assay) is the unique outcome of binding a correct incoming nucleotide, both complementary to the templating base and with a deoxyribose (rather than ribose) sugar structure. Complexes with mispaired dNTPs or complementary rNTPs are arrested at an earlier stage, corresponding to a partially closed fingers conformation, in which weak binding of DNA and nucleotide promote dissociation and resampling of the substrate pool. A 2-aminopurine fluorescence probe on

SUBMITTER: Bermek O 

PROVIDER: S-EPMC3770053 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature