The protein DinG is an ATP-dependent helicase from E. coli that contains a 4Fe-4S cluster. DNA-modified gold electrodes were used to measure the midpoint redox potential of the DNA-bound protein, which was found to be ~80 mV vs. NHE. Using a 20-mer with a 15-mer single-stranded overhang as a helicase substrate on the DNA-modified electrodes, it was shown that enzymatic activity via the hydrolysis of ATP increased the intensity of the electrochemical signal intensity. Whether DinG and EndoIII, a base excision repair enzyme also containing a 4Fe-4S cluster, use DNA-mediated charge transport (CT) chemistry for inter-protein signaling was tested using several techniques. Using a single molecule atomic force microscopy assay, it was shown that DinG and EndoIII preferentially redistribute to strands of DNA that contain DNA damage via long-range DNA-mediated CT. To test this signaling within cells, genetics experiments were used that strongly suggest that DinG and EndoIII utilize DNA-mediated signaling to cooperate in redistributing DinG to its target lesion.

DNA-mediated signaling by the E. coli helicase, DinG

249th National Meeting (2015)

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DNA-mediated signaling by the E. coli helicase, DinG<br />