Sir Aaron Klug, molecular biologist. Sir Aaron Klug (born 1926) studied viruses and other biomolecules using crystallographic electron microscopy. He was awarded the Nobel Prize for Chemistry in 1982 for this work, and determined the structure of several DNA-protein complexes important in cell division. In 1985, his team discovered the structure of zinc fingers, protein-metal ion complexes that bind to DNA and play a role in switching genes on and off. By designing specific zinc finger proteins, selected genes can be deactivated. This can be used to cure some cancers, such as leukaemia. Photographed in 1992.