Rosalind Franklin

Rosalind Elsie Franklin (25 July, 1920 - 16 April, 1958) was a British physical chemist and crystallographer who made important contributions to the understanding of the fine structures of coal and graphite, DNA and viruses.

King's College London 1951-1953

Rosalind Franklin started working as a research associate at King's College London in the Medical Research Council's (MRC) Biophysics Unit, directed by John Randall, at the beginning of January 1951. Originally to have worked on X-ray diffraction of proteins in solution, her work was redirected to DNA fibres. Maurice Wilkins was already carrying out X-ray diffraction analysis of DNA in the Unit (it was one of his photos, shown at a meeting in Naples in May 1951, which inspired James D. Watson to come to Cambridge to do similar research).

Related Topics:
King's College London - Medical Research Council - John Randall - Maurice Wilkins - James D. Watson

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Unfortunately Randall had said that Franklin alone would be working on DNA, without informing Wilkins of the decision. Maurice Wilkins was on holiday when Franklin arrived, and so he returned to find that his research project had been taken over by a newcomer. This was not a good start to a scientific relationship which went progressively downhill. Ultimately Sir Lawrence Bragg of the Cavendish Laboratory at Cambridge gave Watson and Crick the go ahead to resume model making. In doing so, the Cavendish Laboratory team beat not only Linus Pauling but also the King's College London team to the DNA structure, while heavily relying on King's results, especially those of Rosalind Franklin and Raymond Gosling. Both the Cavendish Laboratory and King's College London scientists were working for the Medical Research Council.

Related Topics:
Lawrence Bragg - Cavendish Laboratory - Cambridge

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Discovery of the structure of DNA

Franklin together with her Ph.D. student Raymond Gosling obtained some excellent X-ray diffraction photographs of DNA. They discovered that there were two forms of DNA, at high humidity (when wet) the DNA fibre became long and thin, when it was dried it became short and fat. These were termed DNA A (the dry or crystalline form) and DNA B (the wet or paracrystalline form). In October 1951 relations between Franklin and Wilkins were so bad that the work on DNA was divided, Franklin taking the A form to study and Wilkins the B form. Franklin had the better quality DNA and the better apparatus, but as would become apparent later, the B form was the form which produced the most easily interpretable X-ray diffraction pictures. The X-ray diffraction pictures taken by Franklin at this time have been called, by J. D. Bernal, 'amongst the most beautiful X-ray photographs of any substance ever taken.' In November 1951 King's held a colloquium on nucleic acid structure. Rosalind Franklin and Maurice Wilkins both gave presentations, James Watson was present. Shortly afterwards Francis Crick and Watson put together a model of DNA, but the flaws in the model were spotted immediately by Franklin.

Related Topics:
Raymond Gosling - J. D. Bernal - Francis Crick

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By the beginning of 1952 it was generally accepted in King's that the B form of DNA was a helix and Franklin's photograph 51 seemed to put the question beyond doubt. Because of the agreement not to work on the B form, Franklin never tried to interpret the photograph. In the Summer of 1952 Franklin told Randall that she was leaving King's to go to work at Birkbeck in January 1953. Gosling and Franklin were not convinced that DNA 'A' was a helical molecule. The disadvantage of working on the 'A' form of deoxyribonucleic acid is that it is a much more dense and tightly coiled molecule, which gives diffraction patterns which are more difficult to interpret. In December 1952 members of the department wrote up their work in a report for the MRC. In it, Franklin gave important information about the space group the DNA crystal fell into, 'face-centred monoclinic'. In January 1953 Maurice Wilkins showed James Watson Franklin's photograph 51. Crick and Watson had already obtained much information from Wilkins about the dimensions of the molecule and so started to build a new model. Crick and Watson had also managed to get hold of a copy of the MRC report from the previous December. This contained the unpublished work by Franklin on the DNA crystal's space group, and therefore was not intended to be circulated to other laboratories. Crick and Watson realised this showed that the two chains were antiparallel.

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Watson and Crick succeeded in building a model of the B form of DNA incorporating the data, which was published in Nature on April 25, 1953 in an article describing the double-helical structure of DNA. Upon seeing the Crick and Watson model, Franklin is reported to have commented that it was very pretty 'but how are they going to prove it'. Crick and Watson never did prove their model. Articles by Wilkins and Franklin{{ref|naturearticles}} illuminating their X-ray diffraction data published in the same issue of Nature supported the Crick and Watson model for the B form of DNA. Francis Crick has commented that 'Strictly speaking, our model was not finally decisively proved until some 25 or so years later'. Rosalind Franklin never did work on the B form of DNA, and perhaps never knew that Crick and Watson had seen the MRC report. Franklin eventually left King's College London in March 1953 to move to Birkbeck.

Related Topics:
''Nature'' - Birkbeck

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Rosalind Franklin and DNA

Much has been written on the role that Franklin played in the discovery of the structure of DNA. Her work was an important basis for determining DNA's structure and used extensively by Crick and Watson. Franklin was very close to a solution, but had several obstacles to overcome. The antipathy between her and Maurice Wilkins was the major problem; they got off to a bad start with each other and their working relationship never recovered. This led to Franklin having no real collaborator (and so no one to trade ideas with), and to the two working in seclusion from each other, when they should have been working together. It has been implied by Wilkins himself that this situation may well have been deliberately exacerbated by John Randall. Watson has stated that Franklin ..made some wrong choices. She should have solved the structure early in 1952 {{ref|watson}} (though Rosalind Franklin started to work on DNA in January 1951, just one year earlier); on the other hand, Crick has said Franklin would have made the discovery within three months, if he and Watson had not published their paper. In fact, she had already prepared a draft paper describing the structure as a double helix when Crick and Watson produced theirs.

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Wilkins, Watson, and Crick were awarded the Nobel Prize in Physiology or Medicine in 1962. Franklin had died of ovarian cancer on April 16, 1958 in London; which may have been caused by exposure to X-ray radiation during the course of her research. She is interred in the Willesden Jewish Cemetery in London.

Related Topics:
Nobel Prize in Physiology or Medicine - 1962 - Ovarian cancer - 1958 - Willesden Jewish Cemetery

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