Dr. Graeme Cox is distinguished for contributions to a number of aspects of bacterial physiology using the techniques of biochemistry and molecular biology. In his earlier work he made important contributions in the areas of iron-binding compounds and iron transport, the biosynthesis and function of quinones, and the genetics and assembly of the F0F1-ATPase. His recent site-directed mutagenesis experiments on the mechanism of oxidative phosphorylation have solved the long-standing problem of the nature of the proton channel of the ATP synthase. He has also defined, by site-directed mutagenesis, essential amino acid residues concerned in phosphate transport and transmembrane signalling in the pho regulon in Escherichia coli.