title: A comparative differential scanning calorimetric study of tobacco mosaic virus and of its coat protein ts mutant.
abstract: The differential scanning calorimetry (DSC) 'melting curves' for virions and coat proteins (CP) of wild-type tobacco mosaic virus (strain U1) and for its CP ts mutant ts21-66 were measured. Strain U1 and ts21-66 mutant (two amino acid substitutions in CP: 121 --> T and D66 --> G) differ in the type of symptoms they induce on some host plants. It was observed that CP subunits of both U1 and ts21-66 at pH 8.0, in the form of small (3-4S) aggregates, possess much lower thermal stability than in the virions. Assembly into the virus particles resulted in a DSC melting temperature increase from 41 to 72 degrees C for U1 and from 38 to 72 degrees C for ts21-66 CP. In the RNA-free helical virus-like protein assemblies U1 and ts21-66 CP subunits had a thermal stability intermediate between those in 3-4S aggregates and in the virions. ts21-66 helical protein displayed a somewhat lower thermal stability than U1.
authors.affiliation: A.N. Belozersky Institute of Physical and Chemical Biology, Moscow State University, Russia.
authors.forename: V N
authors.initials: VN
authors.lastname: Orlov
authors.forename: S V
authors.initials: SV
authors.lastname: Kust
authors.forename: P V
authors.initials: PV
authors.lastname: Kalmykov
authors.forename: V P
authors.initials: VP
authors.lastname: Krivosheev
authors.forename: E N
authors.initials: EN
authors.lastname: Dobrov
authors.forename: V A
authors.initials: VA
authors.lastname: Drachev
mesh_terms: D019943:Amino Acid Substitution; D002152:Calorimetry, Differential Scanning / Q000379:methods; D002213:Capsid / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D006358:Hot Temperature; D017354:Point Mutation; D013816:Thermodynamics; D014027:Tobacco Mosaic Virus / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D014771:Virion / Q000737:chemistry / Q000648:ultrastructure