Poster abstracts

Poster number 56 submitted by Brian Maxwell

Multi-step substrate binding mechanism of a Y-family DNA polymease

Brian A. Maxwell (Biophysics Program, The Ohio State University), Zucai Suo (Chemistry and Biochemistry Department, The Ohio State University)

Abstract:
Numerous kinetic, structural, and theoretical studies have established that DNA polymerases adjust their domain structures to enclose nucleotides in their active sites and then rearrange critical active site residues and substrates for catalysis. Additionally, structural studies have revealed a large conformational change between the apoprotein and the DNA-protein binary state for Y-family DNA polymerases. To elucidate the details of the conformational transitions of Dpo4 during substrate binding and catalysis, in this study, the stopped-flow FRET technique was used to monitor changes in distance between various pairs of locations in the protein. In addition to providing new insight into the conformational changes involved in nucleotide binding and incorporation, the results here show that the previously described conformational change between the apo and DNA-bound states of Dpo4 occurs in a mechanistic step distinct from initial formation or dissociation of the binary complex of Dpo4 and DNA. Subsequently, simulation and single-molecule fluorescence experiments have added further insight into this proposed model of DNA binding has.

References:
Xu, C., Maxwell, B. A., Brown, J. A., Zhang, L., and Suo, Z. (2009) PLoS Biol. 7, e1000225
Maxwell, B. A., Xu, C., and Suo, Z. (2014) Biochemistry. 53(11):1768-78

Keywords: FRET, conformational dynamics, DNA polymerase