Max F. Perutz, co-winner of the 1962 Nobel Prize in chemistry, has been named Dunham lecturer at the Medical School.
Perutz and his associate at Cambridge University's medical research council unit for molecular biology--John F. Kendrew--shared the award for their work on the three-dimensional structure of hemoglobin and myoglobin.
The determination of the molecular structure of the two oxygen-carriers ranks as one of the most spectacular achievements of molecular biology. Perutz' picture of the "architecture" of hemoglobin, the protein of red blood cells, represents almost 25 years of intensive research and was made possible by his discovery of a new experimental method of X-ray analysis.
Perutz becomes the tenth Nobel laureate to deliver the Dunham lectures since their establishment 40 years ago. The lectureship honors Edward K. Dunham, who graduated from the Medical School in 1886.
In his book Proteins and Nucleic Acids, Perutz compares protein molecules to animals, in the sense that both have a "three-dimensional anatomy laid out to a definite plan, rigid in some parts and flexible in others, with perhaps some minor variations in different individuals of the same species."
To discover the nature of this anatomy has been the central problem of protein chemistry, one that can be solved only by X-ray analysis. Until 1953 such analysis, however, had proved fruitful only when used to determine the atomic arrangement of simple organic compounds at least a hundred times smaller than protein molecules, which contain hundreds of amino acid residues arranged in definite sequences as polypeptide chains.
Perutz Solves Problem
Perutz discovered in 1953 that by studying the X-ray diffraction pattern from a series of isomorphous heavy atom compounds, each having a heavy atom (such as mercury) attached to a different site on the protein molecule, the problem of discovering the molecular structure of complex proteins could be solved.
So far only two proteins have yielded to X-ray analysis of this type--hemoglobin and myoglobin. The latter, which carries oxygen in the muscles, was the first whose structure was determined. Kendrew's model shows it to be a three-dimensional "lace-work of fabulous complexity," devoid of any regular or simplifying features, apart from the alpha-helix.
Perutz' X-ray studies of hemoglobin have not yet reached the same high degree of resolution and show far less detail than Kendrew's X-ray analysis of myoglobin, which Perutz says "opened a rich mine of stereochemical information about protein structure."
But they reveal that hemoglobin contains four polypeptide chains of roughly equal length, identical in pairs, and structurally complementary. Both hemoglobin and myoglobin have polypeptide chain folds; this characteristic tertiary structure may be fully determined by their amino acid sequence.
A native of Vienna, Perutz completed his undergraduate training there before emigrating to England in 1936. Soon after arriving in England, he began the work which ultimately enabled him to describe the hemoglobin molecule. In 1940 Perutz received his Ph.D. degree at Cambridge University, and in 1954 he was elected a fellow of the Royal Society.
Among previous Dunham lecturers were Nobel laureates William Einthoven, who developed the electrocardiogram, and Sir Frederick Gowland Hopkins, who discovered the growth-stimulating vitamins. Of the 38 lecturers, 13 have come from England; seven from Germany; three each from France, South America and United States; two from Sweden; and one each from Holland, Norway, Belgium, Denmark, Australia, Canada, and Austria.