Rosalind Franklin and DNA Rosalind Franklin and DNA Rosalind Franklin and DNA is a biography of an English chemist Rosalind Franklin (1920–1958) written by her American friend Anne Sayre in 1975. Franklin was a physical chemist who made pivotal research in the discovery of the structure of DNA, known as "the most important discovery" in biology. DNA itself had become "life's most famous molecule". While working at the King's College London in 1951, she discovered two types of DNA called A-DNA and B-DNA. Her X-ray images of DNA indicated helical structure. Her X-ray image of B-DNA (called Photo 51) taken in 1952 became the
Non-helical models of DNA structure The SBS structure was hypothetical, and was not based primarily upon physical evidence. It was created to provide a theoretical solution to the angular momentum problem in DNA replication, which Rodley believed to be otherwise unsolvable. The SBS structure is a modification of the original Watson-Crick structure where, instead of one fully right-handed helical twist every 10 base pairs, there is only a "half"-twist of 5 base pairs’ length, followed immediately by a half-twist in the "opposite" direction (that is, a left-handed half-twist, also of 5 base pairs’ length). This alternating pattern of right- and left-handed half-twists is repeated throughout