In Silico Measurements of Twist and Bend Moduli for β-Solenoid Protein Self-Assembly Units.
We compute potentials of mean force for bend and twist deformations via force pulling and umbrella sampling experiments for four β-solenoid proteins (BSPs) that show promise in nanotechnology applications. In all cases, we find quasi-Hooke's law behavior until the point of rupture. Bending moduli show modest anisotropy for two-sided and three-sided BSPs, and little anisotropy for a four-sided BSP. There is a slight clockwise/counterclockwise asymmetry in the twist potential of mean force, showing greater stiffness when the applied twist follows the intrinsic twist. When we extrapolate to beam theory appropriate for amyloid fibrils of the BSPs, we find bend/twist moduli which are somewhat smaller than those in the literature for other amyloid fibrils. Twist persistence lengths are on the order of a micron, and bend persistence lengths are several microns. Provided the intrinsic twist can be reversed, these results support the usage of BSPs in biomaterials applications.
Department of Physics and Institute for Complex Adaptive Matter, University of California, Davis, California 95616, United States.
Leonard P
LP
Heinz
Department of Physics and Institute for Complex Adaptive Matter, University of California, Davis, California 95616, United States.
Krishnakumar M
KM
Ravikumar
Department of Physics and Institute for Complex Adaptive Matter, University of California, Davis, California 95616, United States.
Daniel L
DL
Cox
D000682:Amyloid / Q000737:chemistry*; D016880:Anisotropy; D003198:Computer Simulation; D008958:Models, Molecular; D036103:Nanotechnology; D011506:Proteins / Q000737:chemistry*
D000682:Amyloid; D011506:Proteins
amyloid fibrils; flexural rigidity; molecular dynamics; nanowires; persistence length; torsional rigidity; β-solenoid proteins