title: Viral capsid equilibrium dynamics reveals nonuniform elastic properties.
abstract: The long wavelength, low-frequency modes of motion are the relevant motions for understanding the continuum mechanical properties of biomolecules. By examining these low-frequency modes, in the context of a spherical harmonic basis set, we identify four elastic moduli that are required to describe the two-dimensional elastic behavior of capsids. This is in contrast to previous modeling and theoretical studies on elastic shells, which use only the two-dimensional Young's modulus (Y) and the bending modulus (κ) to describe the system. Presumably, the heterogeneity of the structure and the anisotropy of the biomolecular interactions lead to a deviation from the homogeneous, isotropic, linear elastic shell theory. We assign functional relevance of the various moduli governing different deformation modes, including a mode primarily sensed in atomic force microscopy nanoindentation experiments. We have performed our analysis on the T = 3 cowpea chlorotic mottle virus and our estimate for the nanoindentation modulus is in accord with experimental measurements.
authors.affiliation: Department of Chemistry and Biophysics Program, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: May
authors.forename: Ankush
authors.initials: A
authors.lastname: Aggarwal
authors.forename: William S
authors.initials: WS
authors.lastname: Klug
authors.forename: Charles L
authors.initials: CL
authors.lastname: Brooks
mesh_terms: D017795:Bromovirus / Q000378:metabolism*; D002213:Capsid / Q000378:metabolism*; D004548:Elasticity; D020342:Finite Element Analysis; D018625:Microscopy, Atomic Force