| Abstract Scope |
Actin filaments (F-actins) are filamentous intracellular proteins present in eukaryotic cells, known for regulating cellular functions including muscle contraction, cell-motility, cell-division, cell-movement, cell-signaling, and formation of cell-junctions. In actin assembly dynamics, actin filaments are severed constitutively by an essential regulatory protein; ADF/Cofilin. Several studies report mechanical properties of F-actins, however, the fundamental mechanisms governing F-actin response to deformation are unknown. Here, we present an in-depth analysis of the F-actin deformation using steered-molecular-dynamics (SMD) simulations. Our findings demonstrate that F-actin deformation response is regulated by the pattern of dissociation of conformational locks at intra-strand and inter-strand G-actin interfaces. F-actin elongation enabled salt bridge formation at the inter-strand interfaces improves the G-actin-G-actin bond strength. Furthermore, we report an inter-strand serrated locking pattern between G-actin subunits, restricting their relative movement, and enabling ability of F-Actin to resist deformation. We also observe that ADF/Cofilin causes structural transmutations in F-actin, thus altering its physical properties. |