BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Linus Pauling’ s manuscript describing incorrect triple helix, Peter Pauling. In 1952, Peter Pauling was a student at Cambridge when his father, Linus, sent him a paper proposing that DNA was a triple helix. James (Jim) Watson eagerly read the paper and realized that Pauling got it wrong.

Detailed explanation-2: -In 1952, he proposed a three-chain helical structure for DNA. Hampered by inadequate data, he was mistaken. The following year, armed with better experimental results, James Watson and Francis Crick used Pauling’s strategic approach and came up with the correct, double-helical structure.

Detailed explanation-3: -To Pauling the strands appeared cylindrical. He guessed then, looking at these black-and-white slides in the darkened seminar room, that DNA was likely to be a helix. No other conformation would fit both Astbury’s x-ray patterns of the molecule and the photos he was seeing.

Detailed explanation-4: -Pauling proposed a triple helix structure with the bases on the outside, but James Watson and Francis Crick ultimately disproved his idea with their famous double helix model. They had succeeded largely because they had access to X-ray crystallography data from scientists at King’s College in London.

Detailed explanation-5: -Pauling and Corey state that they kept the close packing of nucleotides in a helical structure by having three DNA strands wound together, instead of just one strand. The authors summarize how their model of DNA fits with most of the x-ray diffraction evidence.