title: Structural transitions and energy landscape for Cowpea Chlorotic Mottle Virus capsid mechanics from nanomanipulation in vitro and in silico.
abstract: Physical properties of capsids of plant and animal viruses are important factors in capsid self-assembly, survival of viruses in the extracellular environment, and their cell infectivity. Combined AFM experiments and computational modeling on subsecond timescales of the indentation nanomechanics of Cowpea Chlorotic Mottle Virus capsid show that the capsid's physical properties are dynamic and local characteristics of the structure, which change with the depth of indentation and depend on the magnitude and geometry of mechanical input. Under large deformations, the Cowpea Chlorotic Mottle Virus capsid transitions to the collapsed state without substantial local structural alterations. The enthalpy change in this deformation state ΔHind = 11.5-12.8 MJ/mol is mostly due to large-amplitude out-of-plane excitations, which contribute to the capsid bending; the entropy change TΔSind = 5.1-5.8 MJ/mol is due to coherent in-plane rearrangements of protein chains, which mediate the capsid stiffening. Direct coupling of these modes defines the extent of (ir)reversibility of capsid indentation dynamics correlated with its (in)elastic mechanical response to the compressive force. This emerging picture illuminates how unique physico-chemical properties of protein nanoshells help define their structure and morphology, and determine their viruses' biological function.
authors.affiliation: Department of Chemistry, University of Massachusetts, Lowell, Massachusetts; Moscow Institute of Physics and Technology, Moscow, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Kononova
authors.forename: Joost
authors.initials: J
authors.lastname: Snijder
authors.forename: Melanie
authors.initials: M
authors.lastname: Brasch
authors.forename: Jeroen
authors.initials: J
authors.lastname: Cornelissen
authors.forename: Ruxandra I
authors.initials: RI
authors.lastname: Dima
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Marx
authors.forename: Gijs J L
authors.initials: GJ
authors.lastname: Wuite
authors.forename: Wouter H
authors.initials: WH
authors.lastname: Roos
authors.forename: Valeri
authors.initials: V
authors.lastname: Barsegov
mesh_terms: D017795:Bromovirus / Q000502:physiology*; D002213:Capsid / Q000737:chemistry* / Q000502:physiology*; D003198:Computer Simulation; D055595:Mechanical Phenomena; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D013816:Thermodynamics