Dorothy Crowfoot Hodgkin: Pharmaceutical Achiever

Dorothy Crowfoot Hodgkin
Pharmaceutical Achiever

by Mary Ellen Bowden

Dorothy Hodgkin

On the morning in May 1940 that the results of injecting four of eight infected mice with penicillin became known, an excited Ernst Chain encountered Dorothy Hodgkin on Parks Road in Oxford. He knew the brilliant young X-ray crystallographer from her Cambridge days, and as she later recalled, he had promised: “Some day we will have some crystals for you to work on.”

Dorothy Crowfoot was born in Cairo, Egypt, to English parents. Although her formal schooling took place in England, she spent a significant part of her youth in the Middle East and North Africa, where her father was a school inspector. Both her parents were authorities in archaeology, and she almost followed the family vocation; but from childhood she was fascinated by minerals and crystals. She enjoyed using a portable mineral analysis kit given to her when she became interested in analyzing pebbles she and her sister found in the stream that ran through the Crowfoots' garden in Khartoum, Sudan.

When she was fifteen, her mother gave her Concerning the Nature of Things (1925), a popular book by one of the founders of X-ray crystallography, Sir William Henry Bragg. It contained intriguing discussions of how scientists could use X-rays to “see” atoms and molecules. In this method structural information is obtained from the substance under observation by mathematical analysis of the intensity of X-rays scattered (or diffracted) from parallel planes in a crystal, as recorded photographically or by an electronic detector.

Dorothy Mary Crowfoot Hodgkin. Portrait by Maggi Hambling. Oil on canvas, 36.75 inches × 30 inches (932 mm × 760 mm), 1985. This portrait was the first of a woman scientist to be hung in the National Portrait Gallery, London. Courtesy National Portrait Gallery, London.

At Somerville College, Oxford, Crowfoot studied physics and chemistry and chose to do her fourth-year research project on X-ray crystallography, a field for which the equipment at Oxford was primitive. After graduation she seized the opportunity of studying at Cambridge with John Desmond Bernal, who had worked for five years with Bragg at the Royal Institution. Crowfoot and Bernal collaborated successfully, using X-ray crystallography to elucidate the three-dimensional structure of complex and biologically important molecules, including pepsin—the digestive enzyme found in the stomach that was the first protein to be so analyzed. In 1937 Crowfoot received her Ph.D. from Cambridge—the same year she married Thomas L. Hodgkin, a historian who became an authority on Africa. Both Hodgkins held academic appointments at Oxford, and they raised their three children there with the help of the Hodgkin grandparents.

The structural determination of penicillin, one of Hodgkin's greatest chemical achievements, depended on the first step of getting the substance to crystallize (as do all such determinations). The strain of penicillin with which the Americans were working proved easier to crystallize, and a three-milligram sample was flown across the Atlantic for Hodgkin to crystallize personally. To perform the thousands of calculations necessary to transform the two-dimensional X-ray data into three-dimensional atomic positions, the group under Hodgkin's leadership made use of a cast-off punched-card computer, and in 1945 they were able to confirm the beta-lactam structure central to the penicillin molecule (see Howard Florey and Ernst Chain, Figure 1).

For the determination achieved in 1957 of the structure of vitamin B₁₂, the vitamin essential to preventing pernicious anemia, Hodgkin's group started with the old punched-card machine, but in time they used electronic computers in England and in the United States. In 1964 she was awarded the Nobel Prize in chemistry for her work on vitamin B₁₂, the most complex organic molecular structure determined in detail up to that time. In 1969 she completed a three-dimensional structure of insulin—the hormone essential for the control of blood sugar levels—following Frederick Sanger's ordering of insulin's fifty-one amino acids, which brought him the 1958 Nobel Prize in chemistry.

Hodgkin is fondly remembered by her group of research students, which included many women. She was also involved in a wide range of peace and humanitarian causes. From 1976 to 1988 she was chair of the Pugwash movement, which elicits the insights of and input from the world's scientists on potential dangers raised by scientific research.
(Reproduced from Bowden, Mary Ellen. Pharmaceutical Achievers. Philadelphia: Chemical Heritage Foundation, 2002.)
For more information, at other Web sites...

Dorothy Crowfoot Hodgkin — illustrated biography from Pennsylvania State Univeristy.
Martin's Distinctly Succinct Guide to X-ray Crystallography — part of The Molecules of Life from Oxford University.
The Nobel Prize in Chemistry 1958 — includes biographical information on Frederick Sanger as well as descriptions of his prize-winning work.
The Nobel Prize in Chemistry 1964 — includes biographical information on Dorothy Crowfoot Hodgkin as well as descriptions of her prize-winning work.
Remembering Dorothy Hodgkin - a personal reminiscence of Hodgkin by Anne Sayre, reprinted from the ACA Fall 1995 newsletter.
Vitamin B₁₂ — the science and history of the vitamin whose structure Hodgkin elucidated, from Clemson University.

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Image Credits

Dorothy Hodgkin: Courtesy Hodgkin Family and copy from Judith A. K. Howard (Durham, U.K.).
Dorothy Mary Crowfoot Hodgkin. Portrait by Maggi Hambling: Courtesy National Portrait Gallery, London.

Copyright ©2002 The Chemical Heritage Foundation