RefNo | EC/1982/12 |
Previous numbers | Cert XXI, 56 |
Level | Item |
Title | Finch, John Thomas: certificate of election to the Royal Society |
Date | 1979 |
Description | Citation typed |
Citation | Distinguished for his application of electron microscopy and X-ray diffraction to biological assemblies, especially viruses and chromatin. He was the first to show the protein helix of tobacco mosaic virus directly in electron micrographs and to determine its hand by tilting the specimen. He established the 17 fold symmetry of the protein disc which acts as an intermediate in the assembly of that virus, and he showed how its two rings can translocate into a helix. Either alone or with Klug, he determined the surface lattices of many spherical viruses, including tomato bushy stung, R17 bacteriophage, human wart and polyoma, and he proved that these lattices conform to Caspar and Klug's theory. By his tilting experiments, he showed that negatively stained images of viruses represent superpositions of their top and bottom surfaces, rather than "footprints" of only one side, as had been believed. This work set the standards for rigorous fine structure analysis in the electron microscope and paved the way for 3-D image reconstruction. Finch's virus studies using a combination of X-ray diffraction and electron microscopy are models of their kind, and his work on the TMV protein disk laid the basis for its eventual solution to 2.8 A resolution. He was the first to apply image analysis methods to paramyxovirus and bacterial flagella. He identified the enzymatic split products of chromatin as a succession of beads threaded into 100 A thick fibres and showed in vivo these fibres could be coiled into solenoids of three times that thickness. He also obtained electron micrographs and X-ray diffraction pictures of nucleosome crystals which revealed each bead as being made up of a coil of superhelical DNA wrapped around a histone core, and has determined the relative orientation of DNA and core by neutron scattering. |
AccessStatus | Closed |
Fellows associated with this archive
Code | PersonName | Dates |
NA4053 | Finch; John Thomas (1930 - 2017) | 1930 - 2017 |