April 1, 2005  
 

 

An Early X-ray Pioneer Finally Gets Her Due

By Heather Rock Woods

In 1952, Rosalind Franklin (King’s College London) made key images of DNA that contributed to the discovery of the double helix structure of DNA by James Watson and Francis Crick. The two men received the 1962 Nobel Prize, but they gave no credit to her pivotal images and data—which they had seen without her permission or knowledge.

Lynne Osman Elkin, foreground, (CSU, East Bay) gave the March WIS seminar on the pivotal DNA x-ray crystallography work done by Rosalind Franklin.

Photo by Diana Rogers

The speaker at last month’s Women’s Interchange at SLAC (WIS) celebrated Franklin’s crucial role in one of the most significant scientific triumphs in the last century. Lynne Osman Elkin, Professor Emeritus of Biological Sciences at CSU East Bay, is writing a biography on Franklin. Elkin has also appeared in a NOVA documentary on Franklin’s work (which WIS aired on March 14) and published an article on her in Physics Today in March 2003 (http://www.aip.org/pt/vol-56/iss-3/p42.html).

Franklin was a British chemist, an x-ray diffraction expert, and a superb experimentalist. “From 1953 to 1968 she was essentially written out of DNA history,” Elkin said.

Her reappearance in the DNA chronicles—in Watson’s 1968 book The Double Helix, 10 years after her death—didn’t do her justice.

“According to Watson’s book, she is an obnoxious assistant who gets data, won’t give it to her boss, holds up the progress of science and is incompetent at interpreting her own data. That’s their rational for appropriating her data,” Elkin said.

It ultimately took the combined efforts of many theoretical and experimental scientists to solve the structure. The structural arrangement of DNA was a great puzzle: how could such a seemingly simple molecule, made up of just four different types of nucleotides, encode all the directions to tell living things to grow and reproduce?

Franklin’s work shares the same underlying principals as the protein crystallography work now done at SSRL. Proteins, and occasionally DNA, are crystallized to make x-ray diffraction patterns that reveal the structure of large, intricate molecules.

“She was a pioneer in crystallography,” said Ana Gonzalez (ESRD). “The kind of analysis she used is still routinely used today to find heavy atoms in proteins and in DNA.”

SSRL has been a modern pioneer in crystallography methods, and allocates more than a fifth of its beam time to crystallography studies—which play an important role in drug design. “A big difference today is we have much better x-ray sources,” Gonzalez said. “There are differences in the diffraction by proteins, which form well-ordered crystals so you get sharp spots, and the diffraction by DNA, which is more like blobs.”

Half a century ago, making x-ray diffraction patterns of DNA was very difficult, but Franklin was experienced, and a perfectionist. According to Elkin, Franklin spent so much time aligning the x-ray beam perfectly to her samples that it may have contributed to her early death from ovarian cancer at age 37.

Franklin came to King’s College in London in 1951, just seven years after the first clear proof that DNA was the genetic material of life. Relations between Franklin and her new colleague, Maurice Wilkins, got off to a bad start when the head of the lab betrayed Wilkins by giving his project to Franklin.

“They couldn’t stand each other,” Elkin said. “They had diametrically opposite personalities (she was prickly, he was shy), and the head of the lab was a disastrous interpersonal manager.”

Wilkins shared the 1962 Nobel for confirming the structure with his x-ray studies between 1953 and 1959. But before the discovery and confirmation, he shared Franklin’s unpublished data and images with Watson and Crick without her knowledge.

In 1952, Franklin prepared DNA fibers and directed her graduate student, Raymond Gosling, to make a diffraction image of the fibers—the famous Photo 51. The image’s X pattern was evidence of a helix, and contained vital information on the distance between atoms and the distance between the repeating pattern of the molecule (DNA’s two strands are like the banisters on a spiral staircase). At the end of the year she wrote up much of her new data and analysis in an internal report.

Wilkins showed Photo 51 to Watson and Crick at the end of January 1953 and told them about the internal report, which they managed to acquire through their contacts. “In January 1953, where were Watson and Crick without her data? Nowhere,” said Elkin. “At the same time, she was very close to the solution.”

In fact, Elkin said, Crick later estimated Franklin was herself three weeks to three months away from solving the structure of DNA. Her data, combined with strong theoretical suggestions from their colleague Jerry Donohue, made possible Watson and Crick’s correct model in early March 1953. In their Nobel speeches four years after Franklin died, neither Watson nor Crick mentioned her, while Wilkins succinctly acknowledged that she made “valuable contributions.” Elkin wants to show the world how truly valuable these contributions were. She is striving to clarify and bring due recognition to Franklin’s essential part in the brilliant illumination of the elegant structure of DNA.

 

The Stanford Linear Accelerator Center is managed by Stanford University for the US Department of Energy

Last update Wednesday March 30, 2005 by Emily Ball