The Fraser Structure of DNA

Today, the DNA series is continued with a post discussing a mostly correct structure that almost emerged from King’s College in the early 1950s. Although Maurice Wilkins, Rosalind Franklin, and Bruce Fraser each contributed information for the structure, it was Fraser that actually put the pieces together and built a model. Therefore, today’s post will focus on Fraser, a lesser-known player in the DNA story.

Robert Donald Bruce Fraser was born on August 14, 1924 in Ickenham, England. In 1943, he received his first of many degrees – an intermediate Bachelors of Science from Birkbeck College in London. Fraser returned to academics after a stint with the Royal Air Force that lasted from 1943 to 1946. In 1948, he received a Bachelors of Science in Physics and Math from King’s College in London. After receiving this degree, Fraser remained at King’s College for quite some time. He held a Medical Research Council Studentship position for approximately three years and received his Ph.D. in Biophysics in 1951.

During his Ph.D. candidacy, Fraser utilized infrared methods to study DNA samples prepared by his wife, Mary Fraser. The duo used the data gathered from this research to establish the idea that the large base groups in DNA sit perpendicular to the molecular axis – information that was soon published (“Physical Studies of Nucleic Acid: Evidence on the Structure of Deoxyribonucleic Acid from Measurements with Polarized Infra-Red Radiation” by Mary J. Fraser & Robert D.B. Fraser in Nature 167. Link not available).

Although DNA had yet to become a particularly important molecule in terms of research, Fraser was not the only person at King’s College working with it. Maurice Wilkins and Rosalind Franklin were also studying DNA, but neither was inclined to make a model based on their data. In fact, Franklin was strongly against model-building until the structure was completely understood.

Despite this, Fraser decided to try his hand at building a model based on both his own research as well as the research of Wilkins and Franklin. Before beginning, he discussed the molecule with both his soon-to-be famous colleagues. More specifically, he asked how many chains each thought a molecule of DNA would contain. Both said three, based on two pieces of information: a) the measurements and density for water content suggested more than one chain, and b)  two chains wouldn’t seem to fill enough space. Using this information, Fraser began to work on his model.

The structure came together very quickly. It was a rather simple model that consisted of a helical shape with three chains, the phosphate groups on the outside of the molecule, and the base groups stacked in the center. As it would turn out, this model correctly predicted almost all of the key features of DNA – the only fault was the three chain property, something that was becoming a common error.

Although Fraser created an excellent model, it did not receive any credit. As a result of Wilkins’ and Franklin’s views on model building, the structure was not to be published. After completing his doctorate work in 1952, Fraser left London and took a position as the chief of the protein chemistry division for the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Melbourne, Australia.

However, this move did not put Fraser completely out of the DNA picture. In 1953, James Watson and Francis Crick were preparing to publish their structure. Wilkins, upon seeing their model, decided that Fraser should have the opportunity to publish his model before Watson and Crick’s was released. Furthermore, Wilkins wanted credit for his significant work with DNA.

Accordingly, Wilkins contacted Fraser in Australia and asked him to quickly write up his structure for an article in Nature that would be accompanied by a short note from Wilkins. Fraser complied and frantically authored a brief paper titled “The Structure of Deoxyribose Nucleic Acid.” This work took Fraser the entirety of one night, and the next morning he cabled it off to London – a rather expensive process.

Unfortunately, despite Fraser’s hard work, he was once again disappointed.

Upon the arrival of the document in London, Francis Crick decided that it should not be published. Instead, he told Wilkins that Fraser would be acknowledged by him and Watson in their article (“Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid“) and that they would state that Fraser’s paper was “in the press”. In reality, the paper was not in the press and it would, in fact, never be published.

For more information on R.D.B. Fraser’s work, visit the website Linus Pauling and the Race for DNA, available at the Linus Pauling Online portal.

One Response

  1. How is Bruce these days? We were at school together – and there are still a few of us Old Wealdens left. I also visited him in Australia in 1983 but we lost touch a few years ago.

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