Who was the American chemist who also attempted to determine DNA structure?

The American chemist who also attempted to determine DNA's structure was Linus Pauling. Already celebrated for explaining chemical bonding and the structures of proteins, Pauling turned his attention to DNA in the early 1950s.

Pauling proposed a three-stranded DNA model in 1953, but it contained serious errors, including an incorrect arrangement of the phosphate groups and water. His mistaken proposal nevertheless intensified the race to solve DNA's structure. Watson and Crick learned that Pauling was working on the problem and built their own physical models at Cambridge.

Pauling's earlier success with the alpha helix made him a formidable competitor. Watson and Crick ultimately proposed the correct antiparallel double helix, drawing on chemical reasoning, Chargaff's base ratios, and X-ray diffraction evidence from King's College London. Pauling later called his failure to solve DNA's structure one of the biggest disappointments of his life.