Donald Caspar 1927 – 2021

Don Caspar, LMB alumnus, has died at the age of 94. Don first came to the MRC Unit for the Study of the Molecular Structure of Biological Systems (now the LMB) as a Postdoctoral Fellow in 1955. He would become a frequent scientific worker at the Lab over the next 20 years and remained a friend and scientific colleague to many. It was Francis Crick who first recruited Don, to record some single crystal virus diffraction patterns, which he had asserted could test his theory with Jim Watson that “spherical” viruses should have cubic symmetry (tetrahedral, octahedral or icosahedral). Don recognised non-crystallographic icosahedral symmetry axes in his precession photographs of Bushy Stunt Virus crystal from their “spikes of high intensity”. Exploring implications of the icosahedral virus symmetry he had discovered kept him returning to the LMB for the next 20 years; from 1965-1975 he had a small desk at the back of Aaron Klug’s office for his summer visits, nominally to work on a description of his Buckminster Fuller-inspired “tensegrity” models, which provided a basis for Don and Aaron’s 1962 quasi-equivalence theory of virus construction. More…