title: Viscoelastic transition and yield strain of the folded protein.
abstract: For proteins, the mechanical properties of the folded state are directly related to function, which generally entails conformational motion. Through sub-Angstrom resolution measurements of the AC mechanical susceptibility of a globular protein we describe a new fundamental materials property of the folded state. For increasing amplitude of the forcing, there is a reversible transition from elastic to viscoelastic response. At fixed frequency, the amplitude of the deformation is piecewise linear in the force, with different slopes in the elastic and viscoelastic regimes. Effectively, the protein softens beyond a yield point defined by this transition. We propose that ligand induced conformational changes generally operate in this viscoelastic regime, and that this is a universal property of the folded state.
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California, United States of America.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zocchi
mesh_terms: D001696:Biomechanical Phenomena; D055119:Elastic Modulus; D004548:Elasticity; D004560:Electricity; D006046:Gold; D051528:Guanylate Kinases / Q000737:chemistry* / Q000378:metabolism*; D053768:Metal Nanoparticles / Q000737:chemistry; D008954:Models, Biological; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology; D017510:Protein Folding; D014783:Viscosity
chemical_list: D006046:Gold; D051528:Guanylate Kinases