James Watson diffraction data collected by Rosalind Franklin and Raymond Gosling. The controversy arose from Watson and Crick using some of Franklin's unpublished data—without her consent—in their construction of the double helix model of DNA. Franklin's experimental results provided estimates of the water content of DNA crystals and these results were consistent with the two sugar-phosphate backbones being on the outside of the molecule. Franklin personally told Crick and Watson that the backbones had to be on the outside, which was a crucial piece of information; before then, Linus Pauling and Watson and Crick had generated erroneous models with the chains inside
Z-DNA one another in a left-handed fashion. The relationship between Z-DNA and the more familiar B-DNA was indicated by the work of Pohl and Jovin, who showed that the ultraviolet circular dichroism of poly(dG-dC) was nearly inverted in 4 M sodium chloride solution. The suspicion that this was the result of a conversion from B-DNA to Z-DNA was confirmed by examining the Raman spectra of these solutions and the Z-DNA crystals. Subsequently, a crystal structure of "Z-DNA" was published which turned out to be the first single-crystal X-ray structure of a DNA fragment (a self-complementary DNA hexamer d(CG)). It was resolved