Obtaining chemical structures with X-rays is more than just a matter of passing X-rays through crystals and generating data that reveal the final structure. The scientist’s ability to handle the data and ‘see’ the structure is of vital importance, and Dorothy Hodgkin was one of the field’s finest experts.
X-ray crystallography was a relatively new science when Hodgkin began her research, but her gifted intuition and exceptional skill helped to define this field. In 1934, Hodgkin and her mentor, John Desmond Bernal, were the first to successfully use X-ray photographs to identify the structure of a protein – the digestive enzyme pepsin. Hodgkin extended the use of X-ray techniques for solving structures from relatively simple compounds to more complex biochemical substances over the next few decades, work for which she received the Nobel Prize in Chemistry in 1964.
Of Hodgkin’s many important discoveries in biochemistry and medicine, two in particular stand out. The first was the determination of the structure of penicillin in 1945. No molecule of that size had previously been analysed by X-ray crystallography, but Hodgkin and her team solved the structure. This brought crystallography into a new age, in which detecting the structure of a medically important compound using this technique could help create new treatments against diseases. The second notable structure was that of vitamin B12, the essential vitamin that prevents pernicious anaemia, in 1956. At the time, this was considered the crowning triumph of X-ray crystallography, both in respect of the chemical and biological importance of the results and the vast complexity of the structure.