Why was Linus Pauling’s proposed DNA structure incorrect?

Linus Pauling’s proposed structure for DNA—which featured three strands twisted together in a ropelike fashion—was incorrect primarily due to limitations in the data and resources available to him at the time.

His efforts to refine his model were hindered by two main factors:
* Poor Data: He relied on inadequate X-ray diffraction photographs of DNA. Crucially, he did not see the high-quality X-ray images produced by Rosalind Franklin, which ultimately served as the key evidence for James Watson and Francis Crick to identify the correct double helix structure.1
* Lack of Context: Pauling lacked a sufficient understanding of the molecule’s distinct wet and dry forms, which prevented him from accurately modeling its configuration.1

While his specific DNA model was superseded by the double helix, Pauling’s foundational work on the nature of the chemical bond and molecular structure remained highly influential, earning him the 1954 Nobel Prize for Chemistry.1