2011/04/27 by Claus Heussinger, Gregory M. Grason
Biochemistry, Genetics and Molecular Biology · Materials Science · Physics and Astronomy · #Biopolymer #Bundle #Cellular Mechanics and Interactions #Persistence length #Polymer Surface Interaction Studies #Protein filament #RADIUS #Radius of gyration #Skin and Cellular Biology Research #Stiffness #Twist #cond-mat.soft #physics.bio-ph
paper · pdf · doi:10.1063/1.3610431
published as J. Chem. Phys. 135, 035104 (2011) · 15 pages, 9 figures, Appendix
arxiv created 2011/04/27 · openalex publication_date 2011/07/21 · arxiv updated 2012/01/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Inspired by the complex influence of the globular crosslinking proteins on the formation of biofilament bundles in living organisms, we study and analyze a theoretical model for the structure and thermodynamics of bundles of helical filaments assembled in the presence of crosslinking molecules. The helical structure of filaments, a universal feature of biopolymers such as filamentous actin, is shown to generically frustrate the geometry of crosslinking between the "grooves" of two neighboring filaments. We develop a coarse-grained model to investigate the interplay between the geometry of binding and mechanics of both linker and filament distortion, and we show that crosslinking in parallel bundles of helical filaments generates intrinsic torques, of the type that tend to wind the bundle superhelically about its central axis. Crosslinking mediates a non-linear competition between the preference for bundle twist and the size-dependent mechanical cost of filament bending, which in turn gives rise to feedback between the global twist of self-assembled bundles and their lateral size. Finally, we demonstrate that above a critical density of bound crosslinkers, twisted bundles form with a thermodynamically preferred radius that, in turn, increases with a further increase in crosslinking bonds. We identify the stiffness of crosslinking bonds as a key parameter governing the sensitivity of bundle structure and assembly to the availability and affinity of crosslinkers.