AP BIOLOGY

Detailed explanation-1: -In the early 1950s, many scientists were racing to discover the structure of DNA . 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.

Detailed explanation-2: -In 1952, Linus Pauling proposed a triple-stranded helix structure for DNA.

Detailed explanation-3: -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.

Detailed explanation-4: -In 1949, Pauling’s team discovered the molecular basis of sickle-cell anemia. He continued to work on the molecular structure of amino acids and, in the early 1950s, determined the large-scale structures of many proteins, the so-called “alpha-helix.” He also worked, though unsuccessfully, on the structure of DNA.

Detailed explanation-5: -PNAS papers by Linus Pauling, Robert Corey, and Herman Branson in the spring of 1951 proposed the -helix and the -sheet, now known to form the backbones of tens of thousands of proteins.