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
Triple-stranded DNA Triple-stranded DNA Triple-stranded DNA (also known as H-DNA or Triplex-DNA) is a DNA structure in which three oligonucleotides wind around each other and form a triple helix. In triple stranded-DNA, one strand binds to a B-form DNA (Watson–Crick base-pairing) through Hoogsteen base pair or reversed Hoogsteen hydrogen bonds. A thymine (T) nucleobase can bind to a Watson–Crick base-pairing of T-A by a Hoogsteen hydrogen bond. The thymine attaches to the adosine (A) of the origin double stranded DNA to create a T-A*T base-triplet. In acidic conditions, a protonated cytosine, represented as C+, can form a base-triplet with a C-G pair