Direct evidence of the role of ATPγS in the binding of single-stranded binding protein (Escherichia coli) and RecA to single-stranded DNA.
To gain insight into the influence of ATPγS on the competitive binding of RecA and single-stranded binding protein (SSB) on single-stranded DNA (ssDNA), AFM imaging was used to examine the three-dimensional structures of the different complexes formed by the binding of the two proteins on ssDNA in the presence and absence of ATPγS. In the presence of ATPγS, RecA attaches to ssDNA, displacing SSB, to form continuous binding regions that caused considerable elongation of the strand. When ATPγS is absent, RecA could not compete with SSB and only binds at a few sites that correspond to the vacancy in ssDNA left when SSB unbinds. These results provide direct evidence that, while SSB binding affinity to DNA is substantially higher than that of RecA, the presence of ATPγS is sufficient to alter the events and enable RecA coating of DNA.
Li
Bing Shi
BS
Department of Chemistry and Institute for Optical Sciences, University of Toronto, Toronto, Ontario, M5S 3H6 Canada. phbingsl@gmail.com
Goh
M Cynthia
MC
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D001667:Binding, Competitive; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D011485:Protein Binding; D011938:Rec A Recombinases / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D011938:Rec A Recombinases