Sunday, July 27, 2014

Rosalind Franklin and the Beauty of the DNA Structure

Rosalind Franklin (1920-1958)
On July 25, 1920, British biophysicist and X-ray crystallographer Rosalind Elsie Franklin was born. She made the first clear X-ray images of DNA’s structure. Her work was described as the most beautiful X-ray photographs ever taken. Franklin’s ‘Photo 51’ informed Crick and Watson of DNA’s double helix structure for which they were awarded a Nobel Prize.

Rosalind Franklin was born in Notting Hill, London, as the second of five children into an affluent and influential British Jewish family. From early childhood, Franklin showed exceptional scholastic abilities. She was educated at St Paul's Girls' School where she excelled in science, Latin and sports. From the age of 15 on, she knew already that she wanted to become a scientist. Rosalind Franklin enrolled at Newnham College, Cambridge, in 1938 and studied chemistry. In 1941, she was awarded Second Class Honors in her finals, which, at that time, was accepted as a bachelor's degree in the qualifications for employment. When she graduated, Franklin was awarded a research scholarship to do graduate work. She spent a year in R.G.W. Norrish's lab without great success. Norrish recognized Franklin's potential but he was not very encouraging or supportive toward his female student. She went on to work as an assistant research officer at the British Coal Utilisation Research Association, where she studied the porosity of coal—work that was the basis of her 1945 Ph.D. thesis "The physical chemistry of solid organic colloids with special reference to coal." [1] CURA was a young organization and there was less formality on the way research had to be done. Franklin worked fairly independently, a situation that suited her. Franklin worked for CURA until 1947 and published a number of papers on the physical structure of coal.

Franklin's next career move took her to Paris from 1947 to 1950. An old friend introduced her to Marcel Mathieu who directed most of the research in France. He was impressed with Franklin's work and offered her a job as a "chercheur" in the Laboratoire Central des Services Chimiques de l'Etat. Here she learned X-ray diffraction techniques from Jacques Mering. In 1951, Franklin was offered a 3-year research scholarship at King's College in London. With her knowledge, Franklin was to set up and improve the X-ray crystallography unit at King's College. Maurice Wilkins was already using X-ray crystallography to try to solve the DNA problem at King's College. Franklin arrived while Wilkins was away and on his return, Wilkins assumed that she was hired to be his assistant. It was a bad start to a relationship that never got any better. [2]

Wilkins' mistake, acknowledged but never overcome, was not surprising given the climate for women at the university then. Only males were allowed in the university dining rooms, and after hours Franklin's colleagues went to men-only pubs. But Franklin persisted on the DNA project. J. D. Bernal called her X-ray photographs of DNA, "the most beautiful X-ray photographs of any substance ever taken." Between 1951 and 1953 Rosalind Franklin came very close to solving the DNA structure. She was beaten to publication by Crick and Watson in part because of the friction between Wilkins and herself. At one point, Wilkins showed Watson one of Franklin's crystallographic portraits of DNA. When he saw the picture, the solution became apparent to him, and the results went into an article in Nature almost immediately. Franklin's work did appear as a supporting article in the same issue of the journal.[3]

A debate about the amount of credit due to Franklin continues. What is clear is that she did have a meaningful role in learning the structure of DNA and that she was a scientist of the first rank. Franklin moved to J. D. Bernal's lab at Birkbeck College, where she did very fruitful work on the tobacco mosaic virus. She also began work on the polio virus. In the summer of 1956, Rosalind Franklin became ill with cancer. She died less than two years later.

Franklin was never nominated for a Nobel Prize. She had died in 1958 and was therefore ineligible for nomination to the Nobel Prize in 1962 which was subsequently awarded to Crick, Watson, and Wilkins in that year. The award was for their body of work on nucleic acids and not exclusively for the discovery of the structure of DNA. Watson has suggested that ideally Wilkins and Franklin would have been awarded the Nobel Prize in Chemistry.

At yovisto you may enjoy the video lecture 'You say you want a revolution: DNA analysis methods' by Prof. Dr. Qiang Zhou from Berkeley University.



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