| Citation | Distinguished for his contributions to protein crystallography, especially for being the first to solve the structure of a membrane protein. His study of the structure and properties of a stable acyl - chymotrypsin and of a methylated chymotrypsin made important contributions to understanding the enzyme's mechanism of action. The analysis used a crystallographic theory of the difference Fourier synthesis, developed with J.K. Moffat. Using X-ray diffraction, he discovered that the purple membrane protein of Halobacterium contains parallel alpha-helices. He then initiated the studies in which he and P.N.T. Unwin solved the three-dimensional arrangement of these helices by low dose electron microscopy of the trigonal membrane crystals. Henderson confirmed this structure by an independent analysis of an orthorhombic modification of the same protein and he also determined its polarity in the membrane. He and his coworkers have used similar methods to find the external shape of cytochrome-oxidase. |