| Citation | Distinguished for his work on the molecular mechanisms of genetic recombination. West demonstrated, initially together with the late Paul Howard-Flanders, that homologous pairing between regions of two duplex DNA molecules can occur within helical filaments generated by the E. coli RecA protein. These synaptic intermediates were subsequently found by West to be cleaved and resolved by a previously unrecognised E. coli activity, the RuvC protein. This long-sought resolving enzyme requires homologous sequences and does not act on static cruciform DNA structures. In a further development, ATP-dependent branch migration in recombination, which may follow initial DNA pairing and exchange promoted by RecA protein, was shown to be due to the inducible RuvA and RuvB proteins. West's work is precise and elegant, and his findings represent major advances in our understanding of homologous recombination processes. |