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Molecular Biology

Dr. M. F. Perutz

Bragg's period of office in Cambridge coincides with the decline of the Cavendish Laboratory as the world's leading centre of atomic physics. This was an inevitable consequence of the war and the transformation of atomic physics to "Big Science", to which the tradition and structure of Cambridge University were ill-adapted. Rather than fight a rearguard action, Bragg decided to back two new applications of physics in which the Cavendish was again to lead the world.

One of these, the build-up of molecular biology, took place gradually after the war, as J.C. Kendrew, F.H.C. Crick, H.E. Huxley, J.D. Watson and V.M. Ingram joined us in successive years. At first finance was a nightmare. Bragg felt that we could not continue to impose upon the generosity of the Rockefeller Foundation which had supported me from 1939 onwards. So he put me up for an l.C.I. Research Fellowship and found some other temporary grant for Kendrew, but by 1947 these sources of finance were approaching their end, and the University offered no help.

At this desperate juncture D. Keilin, the late Professor of Biology, suggested an approach to the Medical Research Council. In traditional fashion, Bragg met Sir Edward Mellanby, the Secretary of the MRC, for luncheon at the Athenaeum Club. Bragg explained that Kendrew and I were out on a treasure hunt with only the remotest chance of success but that, if we did succeed, our results would provide an insight into the workings of life on the molecular scale. Even then it might take a very long time before they would bring any direct benefit to medicine. Mellanby took the risk.

An MRC Research Unit was set up consisting initially of just Kendrew and me. By now this has developed into the MRC Laboratory of Molecular Biology which houses over a hundred scientists. Bragg's far-sighted backing was first rewarded in 1953, just before he left the Cavendish Laboratory, when Watson and Crick solved the problem of DNA; Huxley, by then at MIT, together with Jean Hanson, discovered the sliding mechanism of muscle contraction, and I solved the phase problem in haemoglobin. The first spectacular successes of protein crystallography came a few years later with the solution of the structure of haemoglobin by my colleagues and myself.

The other new application of physics which Bragg helped to initiate at the Cavendish Laboratory was Radio Astronomy. During the war, Martin Ryle, a young Cambridge physicist working on radar, had become interested in radar operators' reports of signals from the sun and the galaxy. Joining J.A. Ratcliffe, a lecturer in physics who studied the ionosphere, Ryle constructed the first radio-telescope from ex-War Department components. Bragg realised the promise of Ryle's early attempts at detecting radio signals from outer space; besides, the location of these signals by interferometry intrigued him as a problem in optics. When, some years later, Ryle and Ratcliffe decided to set up a large radio-telescope near Cambridge, Bragg warmly supported their approach to industry which resulted in the endowment of the Mullard Radio Observatory. In time this led to the discovery of quasars and pulsars and the mapping of radio sources in the most distant parts of the Universe.