Molecular mechanics of coiled coils loaded in the shear geometry.

摘要: Coiled coils are important nanomechanical building blocks in biological and biomimetic materials. A mechanistic molecular understanding of their structural response to mechanical load is essential for elucidating role tissues utilizing tuning these materials applications. Using a combination single-molecule force spectroscopy (SMFS) steered dynamics (SMD) simulations, we have investigated the mechanics synthetic heterodimeric coiled different length (3–4 heptads) when loaded shear geometry. Upon shearing, observe an initial rise force, which followed by constant plateau ultimately strand separation. The required separation depends on coil applied loading rate, suggesting that shearing occurs out equilibrium. This out-of-equilibrium behaviour determined complex involves helix uncoiling, uncoiling-assisted sliding helices relative each other direction as well dissociation perpendicular axis. These processes follow hierarchy timescales with uncoiling being faster than dissociation. In SMFS experiments, dominated at forces between 25–45 pN shortest 3-heptad 35–50 longest 4-heptad coil. values highly similar apart short double-stranded DNA oligonucleotides, reinforcing potential applications where protein-based structures desired.