Citation | Distinguished for his contributions to the electron microscopy of biological specimens, he combines great originality with theoretical insight and experimental skill. He invented an ingenious phase contrast device made of gold-plated gossamer thread stretched over a small aperture. He designed a method of preserving unstained specimens in the electron beam, and together with R. Henderson used this to solve the structure of the purple membrane protein from Halobacterium, unravelling its array of alpha-helices. He demonstrated the arrangement of the large and small ribosomal subunits relative to their supporting membrane and discovered a protrusion anchoring the large subunit to that membrane. Together with G. Zamphigi he found gap junctions to be made of an allosteric protein whose six subunits can turn relative to each other, thereby opening or closing a central channel through which substances can pass from cell to cell. |