Remarks about protein structure precision

Durward Cruickshank joined E. G. Cox's chemical crystallography group at Leeds University in 1946. Cox was a pioneer from 1937 onwards of X-ray structure analysis with three-dimensional data, and the Leeds laboratory was strong in computing by punched-card methods. Cruickshank published on the accuracy of crystal structure analysis by Fourier and least-squares methods from 1949 onwards. In September 1950 Cox sent him to the world's first summer school on electronic computing run at the EDSAC laboratory in Cambridge. From 1952 to 1957 the Leeds group made very heavy use of the Ferranti Mark I computer at Manchester University. This machine was the commercial version of the first electronic stored-program computer, built and run by F. C. Williams and T. Kilburn in 1948. The computation of Booth's differential syntheses for structure refinement led directly to Cruickshank's 1956 papers in Acta Crystallographica on anisotropic atomic vibrations, molecular rigid-body vibrations and libration corrections and to the refinement of J. M. Robertson's structure for anthracene. His later interests have included the structures of second-row oxides, gas-phase electron diffraction and theoretical chemistry. From 1962 to 1967 he was the colleague of Robertson at Glasgow University as Joseph Black Professor of Chemistry. Since 1967 be has been at the University of Manchester Institute of Science and Technology. Early retirement in 1983 has allowed him time for research as a hobby. He had a happy collaboration with John Helliwell and Keith Moffat in the revival of the Laue method as a tool in time-resolved macromolecular crystallography. With N. Kato and H. J. Juretschke he edited the 1992 IUCr Memorial Volume for P. P. Ewald. He has been IUCr Treasurer (1966-1972) and General Secretary (1970-1972). (C) 1999 International Union of Crystallography Printed in Denmark - all rights reserved.