information:highlighting
RNA research

Franklin continued to explore another major nucleic acid, RNA, a molecule equally central to life as DNA. She again used X-ray crystallography to study the structure of the tobacco mosaic virus (TMV), an RNA virus. Her meeting with Aaron Klug in early 1954 led to a longstanding and successful collaboration. Klug had just then earned his PhD from Trinity College, Cambridge, and joined Birkbeck in late 1953. In 1955, Franklin published her first major works on TMV in Nature, where she described that all TMV virus particles were of the same length. This was in direct contradiction to the ideas of the eminent virologist Norman Pirie, though Franklin's observation ultimately proved correct.

Franklin assigned the study of the complete structure of TMV to her PhD student Holmes. They soon discovered (published in 1956) that the covering of TMV was protein molecules arranged in helices. Her colleague Klug worked on spherical viruses with his student Finch, with Franklin coordinating and overseeing the work. As a team, from 1956 they started publishing seminal works on TMV, cucumber virus 4 and turnip yellow mosaic virus.

Franklin also had a research assistant, James Watt, subsidised by the National Coal Board and was now the leader of the ARC group at Birkbeck. The Birkbeck team members continued working on RNA viruses affecting several plants, including potato, turnip, tomato and pea. In 1955 the team was joined by an American post-doctoral student Donald Caspar. He worked on the precise location of RNA molecules in TMV. In 1956, Caspar and Franklin published individual but complementary papers in the 10 March issue of Nature, in which they showed that the RNA in TMV is wound along the inner surface of the hollow virus. Caspar was not an enthusiastic writer, and Franklin had to write the entire manuscript for him.

Franklin's research grant from ARC expired at the end of 1957, and she was never given the full salary proposed by Birkbeck. After Bernal requested ARC chairman Lord Rothschild, she was given a one-year extension ending in March 1958.

Expo 58, the first major international fair after World War II, was to be held in Brussels in 1958. Franklin was invited to make a five-foot high model of TMV, which she started in 1957. Her materials included table tennis balls and plastic bicycle handlebar grips. The Brussels world's fair, with an exhibit of her virus model at the International Science Pavilion, opened on 17 April, one day after she died.