Who she was
Dorothy Crowfoot was born in Cairo in 1910 and became fascinated by crystals as a child. At Oxford she was one of only a handful of women studying chemistry. After graduating in 1932 she joined the physicist J. D. Bernal in Cambridge, where X-ray crystallography was being turned on the molecules of life. She returned to Oxford in 1934 and spent most of her career there.
How X-ray crystallography works
When X-rays pass through a crystal, they are scattered by the electrons of the atoms and produce a pattern of spots. From the positions and intensities of thousands of spots, a crystallographer can calculate where the electron density is, and so where every atom sits in the molecule. In the 1940s and 1950s this meant enormous calculations, done first by hand and later with some of the earliest computers.
Key idea
Hodgkin showed that X-ray crystallography could determine the full three-dimensional structure of large, complex biological molecules, where chemical methods alone had failed.
Key discoveries
- Penicillin (1945). Chemists disagreed about its structure. Hodgkin’s analysis proved that penicillin contains a β-lactam: a strained four-membered ring containing an amide. Knowing the structure helped chemists make new penicillins.
- Vitamin B12 (published 1956). A molecule of more than 90 non-hydrogen atoms built around a cobalt ion, needed to prevent pernicious anaemia. Solving it was a landmark in both crystallography and computing, and the main reason for her Nobel Prize.
- Insulin (1969). She first photographed insulin crystals in 1935 and returned to it for 34 years until the structure of this 51-amino-acid hormone was finally solved, helping scientists understand how it works in the treatment of diabetes.
Prizes and legacy
Hodgkin won the 1964 Nobel Prize in Chemistry alone, “for her determinations by X-ray techniques of the structures of important biochemical substances”. She was the third woman to win the chemistry prize, after Marie Curie and Irène Joliot-Curie. She did much of this work while living with severe rheumatoid arthritis, which affected her hands from her late twenties. She was also a dedicated teacher and campaigned for peace and for scientists in developing countries.
Connections to your lessons
Her work links to molecular shapes (three-dimensional structure), bonding (electron density), and functional groups (the amide in the β-lactam ring).
Timeline
- 1910Born in Cairo; her parents worked in archaeology and education.
- 1928Begins studying chemistry at Somerville College, Oxford, one of very few women in the subject.
- 1932Graduates and moves to Cambridge to work with J. D. Bernal on X-ray crystallography.
- 1934With Bernal, takes the first X-ray diffraction photograph of a protein crystal (pepsin). Returns to Oxford.
- 1937Receives her PhD (on sterols) and marries the historian Thomas Hodgkin.
- 1945Determines the structure of penicillin, proving it contains the strained four-membered β-lactam ring.
- 1956Publishes the structure of vitamin B12, one of the most complex molecules then known, solved with early computers.
- 1964Wins the Nobel Prize in Chemistry.
- 1969Solves the structure of insulin, 34 years after her first X-ray photographs of insulin crystals.
- 1970Becomes Chancellor of the University of Bristol (until 1988).
- 1994Dies at home in Warwickshire.
Sources and further reading
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