Max Perutz the onset of Huntington disease is related to the number of glutamine repeats as they bind to form what he called a polar zipper. During the early 1950s, while Watson and Crick were determining the structure of deoxyribonucleic acid (DNA), they made use of unpublished X-ray diffraction images taken by Rosalind Franklin, shown at meetings and shared with them by Maurice Wilkins, and of Franklin's preliminary account of her detailed analysis of the X-ray images included in an unpublished 1952 progress report for the King's College laboratory of Sir John Randall. Randall and others eventually criticised the manner in which
James Watson determined that their results were inconclusive and could not specifically identify the newly labeled molecules as DNA. Watson never developed a constructive interaction with Kalckar, but he did accompany Kalckar to a meeting in Italy, where Watson saw Maurice Wilkins talk about his X-ray diffraction data for DNA. Watson was now certain that DNA had a definite molecular structure that could be elucidated. In 1951, the chemist Linus Pauling in California published his model of the amino acid alpha helix, a result that grew out of Pauling's efforts in X-ray crystallography and molecular model building. After obtaining some results from