Fluctuating Nonlinear Spring Model of Mechanical Deformation of Biological Particles

• DOI: 10.1371/journal.pcbi.1004729
• Publication Date: 2016-01-28T13:35:58Z
• Authors: Olga Kononova; Joost Snijder; Yaroslav Kholodov; Kenneth A. Marx; Gijs J. L. Wuite; Wouter H. Roos; Valeri Barsegov
• Keywords: DYNAMICS; Simulations; 0301 basic medicine; QH301-705.5; Protein Conformation; FOS: Physical sciences; NANOINDENTATION; Condensed Matter - Soft Condensed Matter; Molecular Dynamics Simulation; ADENOVIRUS; ELASTIC PROPERTIES; 03 medical and health sciences; NANOPARTICLES; Physics - Biological Physics; Biology (General); Virion; Computational Biology; IN-SILICO; Dynamics; Biomechanical Phenomena; 3. Good health; BROME MOSAIC-VIRUS; Nonlinear Dynamics; Biological Physics (physics.bio-ph); Soft Condensed Matter (cond-mat.soft); Capsid Proteins; VIRAL CAPSIDS; Research Article

We present a new theory for modeling forced indentation spectral lineshapes of biological particles, which considers non-linear Hertzian deformation due to an indenter-particle physical contact and bending deformations of curved beams modeling the particle structure. The bending of beams beyond the critical point triggers the particle dynamic transition to the collapsed state, an extreme event leading to the catastrophic force drop as observed in the force (F)-deformation (X) spectra. The theory interprets fine features of the spectra: the slope of the FX curves and the position of force-peak signal, in terms of mechanical characteristics --- the Young's moduli for Hertzian and bending deformations E_H and E_b, and the probability distribution of the maximum strength with the strength of the strongest beam F_b^* and the beams' failure rate m. The theory is applied to successfully characterize the $FX$ curves for spherical virus particles --- CCMV, TrV, and AdV.