Surprising Wilkins’ error (Nature 1953, 172: 755–762)

Abstract

The Nobel Prize in Physiology or Medicine 1962 was awarded jointly to Francis Harry Compton Crick, James Dewey Watson and Maurice Hugh Frederick Wilkins “for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material”. Building the scale atomic-molecular models and applying strong inference Watson and Crick (1953a,b) presented convincing evidences for the following features of the spatial structure of the DNA molecule: (i) this structure has two helical chains each coiled round the same axis; (ii) both chains follow right-handed helices; (iii) the sequences of the atoms in the two chains run in opposite directions; (iv) the two chains are held together by hydrogen-bonded purine and pyrimidine bases; (v) the planes of the bases are perpendicular to the fibre axis; (vi) only specific pairs of bases can bond together: adenine (purine) with thymine (pyrimidine), and guanine (purine) with cytosine (pyrimidine). X-ray evidence obtained at the same time by Wilkins et al. (1953a,b), and Franklin et al. (1953a,b) gave qualitative support to this structure and was incompatible with all previously proposed structures. Wilkins et al. (1953b) built molecular models of the type described by Watson and Crick (1953a) and adjusted them to conform with their experimental data. However, it appeared that the paper by Wilkins et al. (1953b) contains a curious and inexplicable error. Namely, in their Figure 3 DNA is schematically drawn as a left-handed helix, which, as Crick and Watson (1954) explained, is stereochemically impossible and must be right-handed. The fact stated here was mysteriously not noticed before and, fortunately, had no detrimental effect on the development of science.