Rosalind Franklin and DNA best evidence for the structure of DNA. For the discovery of the correct chemical structure of DNA, the Nobel Prize in Physiology or Medicine 1962 was shared by her colleagues and close researchers James Watson, Francis Crick and Maurice Wilkins; she died four years earlier in 1958 making her inelligible for the award. Rosalind Franklin joined the King's College London in January 1951 to work on the crystallography of DNA. By the end of that year, she established two important facts: one is that phosphate groups, which are the molecular backbone for the nucleotide chains, lie on the outside (it
Non-helical models of DNA structure have about 400,000 helical twists in the Watson–Crick model, each of which would have to be removed in as little as 20 minutes, if the strands are to separate during cell replication. This leads to the apparent need of the chromosome - or at least some part of it - to be spinning at speeds up to 6900–9000 rpm throughout the life of the bacterial cell. In 1976, Gordon Rodley and his co-workers published the first non-helical DNA structure, which they named the "side-by-side" (SBS) structure. A similar model was published a few months later by Sasisekharan and his associates.