Molecular models of DNA simulations that are very important to understand how DNA functions "in vivo". From the very early stages of structural studies of DNA by X-ray diffraction and biochemical means, molecular models such as the Watson-Crick nucleic acid double helix model were successfully employed to solve the 'puzzle' of DNA structure, and also find how the latter relates to its key functions in living cells. The first high quality X-ray diffraction patterns of A-DNA were reported by Rosalind Franklin and Raymond Gosling in 1953. Rosalind Franklin made the critical observation that DNA exists in two distinct forms, A and B, and produced
Francis Crick collected by Gosling and Franklin provided the best evidence for the helical nature of DNA. Franklin's experimental work thus proved crucial in Watson and Crick's discovery. Her experimental results provided estimates of the water content of DNA crystals, and these results were most consistent with the three sugar-phosphate backbones being on the outside of the molecule. Franklin's X-Ray photograph showed that the backbones had to be on the outside. Although she at first insisted vehemently that her data did not force one to conclude that DNA has a helical structure, in the drafts she submitted in 1953 she argues for