Tension-induced binding of semiflexible biopolymers

Tension-induced binding of semiflexible biopolymers

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We investigate theoretically the effect of polymer tension on the collective behavior of reversibly binding cross-links.For this purpose, we employ a model of two weakly bending wormlike chains aligned in parallel by a tensile force, with a sequence of inter-chain binding sites regularly spaced along click here the contours.Reversible cross-links attach and detach at the sites with an affinity controlled by a chemical potential.In a mean-field approach, we calculate the free energy of the system and find the emergence of a free-energy barrier which controls the reversible (un)binding.The tension affects the conformational entropy of the chains which competes with the binding energy of the cross-links.

This competition gives rise to a sudden increase wilds of eldraine prerelease guide in the fraction of bound sites as the tension increases.We show that this transition is related to the cross-over between weak and strong localization of a directed polymer in a pinning potential.The cross-over to the strongly bound state can be interpreted as a mechanism for force-stiffening which exceeds the capabilities of single-chain elasticity and thus available only to reversibly cross-linked polymers.