X-Ray Diffraction and the Architecture of Viruses
Delivered at King's College London / Birkbeck in 1952, presenting her groundbreaking X-ray diffraction images (including Photo 51) that revealed the helical structure of DNA.
Full Transcript
Science and everyday life cannot and should not be separated.
When analyzing crystalline structures using X-ray diffraction, we observe diffraction patterns produced by the scattering of X-rays by electron clouds surrounding atomic nuclei.
In our investigations at King’s College, we have obtained distinct B-form crystalline patterns from hydrated DNA fibers. The two-dimensional scattering pattern—showing a sharp X-shaped reflection—provides unambiguous quantitative evidence of a double helical structure with phosphate groups on the outside.
Furthermore, applying these crystallographic techniques to plant viruses, such as Tobacco Mosaic Virus, reveals a helical arrangement of protein subunits surrounding a central nucleic acid core.
Finding facts and discerning the underlying mathematical symmetry of biological molecules is a reward in itself.
Defining Key Excerpts
"Science and everyday life cannot and should not be separated."
"In my view, all that is necessary for a faith is the belief that by doing our best we shall come nearer to success and that the pleasure in finding facts is a reward in itself."
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