title: The organization of potato virus X coat proteins in virus particles studied by tritium planigraphy and model building.
abstract: Potato virus X particles containing the intact, undegraded Ps form of the coat protein and particles containing the in situ degraded Pf form of the coat protein, which is devoid of 19-21 amino acids from the N-terminus, were bombarded with thermally activated tritium atoms, and the intramolecular distribution of the tritium label was studied. The tritium planigraphy revealed that the N-terminal region of the coat protein is the most accessible region for both type of PVX particles. The C-terminal region of the coat protein in the intact virus particles is almost inaccessible to the hot tritium atoms, whereas in Pf particles this region becomes available for the tritium label. A model of PVX coat protein tertiary structure was built, taking into account the predicted secondary structure of the protein, the principles of packing alpha-helices and beta-structure in globular proteins, and known biochemical, immunological, and tritium bombardment data. In the model one beta-sheet consisting of beta-strands at regions 1-12, 14-22, and 24-33 flanks the molecule and forms the outside surface of the PVX particles.
authors.affiliation: A. N. Belozersky Laboratory of Molecular Biology and Bioorganic Chemistry, Moscow State University, Russia.
authors.forename: L A
authors.initials: LA
authors.lastname: Baratova
authors.forename: N I
authors.initials: NI
authors.lastname: Grebenshchikov
authors.forename: E N
authors.initials: EN
authors.lastname: Dobrov
authors.forename: A V
authors.initials: AV
authors.lastname: Gedrovich
authors.forename: I A
authors.initials: IA
authors.lastname: Kashirin
authors.forename: A V
authors.initials: AV
authors.lastname: Shishkov
authors.forename: A V
authors.initials: AV
authors.lastname: Efimov
authors.forename: L
authors.initials: L
authors.lastname: Järvekülg
authors.forename: Y L
authors.initials: YL
authors.lastname: Radavsky
authors.forename: M
authors.initials: M
authors.lastname: Saarma
mesh_terms: D000595:Amino Acid Sequence; D002213:Capsid / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010942:Plant Viruses / Q000737:chemistry*; D010947:Plants, Toxic; D011487:Protein Conformation; D014026:Nicotiana; D014056:Tomography, X-Ray; D014316:Tritium
chemical_list: D014316:Tritium