Oxford University Press, Nucleic Acids Research, 17(40), p. 8743-8758, 2012
DOI: 10.1093/nar/gks633
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UvrB has a central role in the highly conserved UvrABC pathway functioning not only as a damage recognition element but also as an essential component of the lesion tracking machinery. While it has been recently confirmed that the tracking assembly comprises a UvrA(2)B(2) heterotetramer, the configurations of the damage engagement and UvrB-DNA handover complexes remain obscure. Here, we present the first crystal structure of a UvrB dimer whose biological significance has been verified using both chemical cross-linking and electron paramagnetic resonance spectroscopy. We demonstrate that this dimeric species stably associates with UvrA and forms a UvrA(2)B(2)-DNA complex. Our studies also illustrate how signals are transduced between the ATP and DNA binding sites to generate the helicase activity pivotal to handover and formation of the UvrB(2)-DNA complex, providing key insights into the configurations of these important repair intermediates.