title: Partially disordered structure in intravirus coat protein of potyvirus potato virus A.
abstract: Potyviruses represent the most biologically successful group of plant viruses, but to our knowledge, this work is the first detailed study of physicochemical characteristics of potyvirus virions. We measured the UV absorption, far and near UV circular dichroism spectra, intrinsic fluorescence spectra, and differential scanning calorimetry (DSC) melting curves of intact particles of a potato virus A (PVA). PVA virions proved to have a peculiar combination of physicochemical properties. The intravirus coat protein (CP) subunits were shown to contain an unusually high fraction of disordered structures, whereas PVA virions had an almost normal thermal stability. Upon heating from 20 °C to 55 °C, the fraction of disordered structures in the intravirus CP further increased, while PVA virions remained intact at up to 55 °C, after which their disruption (and DSC melting) started. We suggest that the structure of PVA virions below 55 °C is stabilized by interactions between the remaining structured segments of intravirus CP. It is not improbable that the biological efficiency of PVA relies on the disordered structure of intravirus CP.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Ksenofontov
authors.forename: Viiu
authors.initials: V
authors.lastname: Paalme
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Arutyunyan
authors.forename: Pavel I
authors.initials: PI
authors.lastname: Semenyuk
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Fedorova
authors.forename: Reet
authors.initials: R
authors.lastname: Rumvolt
authors.forename: Ludmila A
authors.initials: LA
authors.lastname: Baratova
authors.forename: Lilian
authors.initials: L
authors.lastname: Järvekülg
authors.forename: Eugeny N
authors.initials: EN
authors.lastname: Dobrov
mesh_terms: D002152:Calorimetry, Differential Scanning; D036022:Capsid Proteins / Q000737:chemistry*; D017800:Potyvirus / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D011487:Protein Conformation; D017510:Protein Folding; D013057:Spectrum Analysis; D013816:Thermodynamics; D014771:Virion / Q000737:chemistry / Q000302:isolation & purification / Q000648:ultrastructure
chemical_list: D036022:Capsid Proteins