William Lawrence Bragg

In 1915 the youngest Nobel prize winner ever was announced: William Lawrence Bragg, who was 25 at the time. Together with his father William Henry Bragg he had developed X-ray crystallography and as a byproduct found Bragg’s Law which describes the scattering of waves from a crystal lattice. The reemitted wave fields interfere with each other either constructively or destructively, producing a distinctive diffraction pattern. The resulting wave interference pattern is the basis of diffraction analysis, a method called Bragg diffraction.

Originally the method had only been used for simple crystals in material science and geology, but after the Second World War it soon became clear that it could be put to great use to determine the structure and function of many biological molecules, mainly thanks to the work of Dorothy Crowfoot Hodgkin, who found the structures of cholesterol (1937), penicillin (1946) and vitamin B12 (1956) and later of insulin. For her first accomplishments she herself was awarded a Nobel Prize, almost exactly fifty years after the Braggs, in 1964. RNA structure analysis on the other hand proved to be a difficult task. In 1965 Holley et al. sequenced the first tRNA molecule, proposing structural elements as well, but after these first achievements the field of RNA structure did not dramatically advance for over two decades, until the coming of NMR as the second powerful technique in structural biology research. Recently, Ada Yonath, Venkatraman Ramakrishnan, and Thomas Steitz were awarded the 2009 Nobel Prize in Chemistry for their structural work on the ribosome.

A hundred years ago, the Nobel prize committee honoured the two Braggs with the following, indeed somewhat prophetic words: “Thanks to the methods that the Braggs, father and son, have devised for investigating crystal structures, an entirely new world has been opened and has already in part been explored with marvellous exactitude. The significance of these methods, and of the results attained by their means, cannot as yet be gauged in its entirety, however imposing its dimensions already appear to be.”

by Roland Fischer