Aaron Klug. British molecular biologist Sir Aaron Klug (born 1926) with a molecular model of a 'zinc finger', a protein-zinc complex that can bind to DNA and switch genes on and off. The atoms are colour-coded: carbon (black), hydrogen (white), nitrogen (blue) and oxygen (red). Zinc fingers can be used to cure some cancers, such as leukaemia, and were discovered by Klug's research team in 1985. Klug received the Nobel Prize for Chemistry in 1982, for his work on crystallographic electron microscopy. He used this technique to determine the structure of several DNA-protein complexes important in cell division. Photographed in 1995.