Active dynamics of charged macromolecules

Fuente: arXiv
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Main Authors: Singha, Tapas, Li, Siao-Fong, Muthukumar, Murugappan
Format: Preprint
Published: 2024
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author Singha, Tapas
Li, Siao-Fong
Muthukumar, Murugappan
author_facet Singha, Tapas
Li, Siao-Fong
Muthukumar, Murugappan
contents We study the role of active coupling on the transport properties of homogeneously charged macromolecules in an infinitely dilute solution. An enzyme becomes actively bound to a segment of the macromolecule, exerting an electrostatic force on it. Eventually, thermal fluctuations cause it to become unbound, introducing active coupling into the system. We study the mean-squared displacement (MSD) and find a new scaling regime compared to the thermal counterpart in the presence of hydrodynamic and segment-segment electrostatic interactions. Furthermore, the study of segment-segment equal-time correlation reveals the swelling of the macromolecule. Further, we derive the concentration equation of the macromolecule with active binding and study how the cooperative diffusivity of the macromolecules get modified by its environment, including the macromolecules itself. It turns out that these active fluctuations enhance the effective diffusivity of the macromolecules. The derived closed-form expression for diffusion constant is pertinent to the accurate interpretation of light scattering data in multi-component systems with binding-unbinding equilibria.
format Preprint
id arxiv_https___arxiv_org_abs_2405_13963
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Active dynamics of charged macromolecules
Singha, Tapas
Li, Siao-Fong
Muthukumar, Murugappan
Soft Condensed Matter
Biological Physics
Chemical Physics
We study the role of active coupling on the transport properties of homogeneously charged macromolecules in an infinitely dilute solution. An enzyme becomes actively bound to a segment of the macromolecule, exerting an electrostatic force on it. Eventually, thermal fluctuations cause it to become unbound, introducing active coupling into the system. We study the mean-squared displacement (MSD) and find a new scaling regime compared to the thermal counterpart in the presence of hydrodynamic and segment-segment electrostatic interactions. Furthermore, the study of segment-segment equal-time correlation reveals the swelling of the macromolecule. Further, we derive the concentration equation of the macromolecule with active binding and study how the cooperative diffusivity of the macromolecules get modified by its environment, including the macromolecules itself. It turns out that these active fluctuations enhance the effective diffusivity of the macromolecules. The derived closed-form expression for diffusion constant is pertinent to the accurate interpretation of light scattering data in multi-component systems with binding-unbinding equilibria.
title Active dynamics of charged macromolecules
topic Soft Condensed Matter
Biological Physics
Chemical Physics
url https://arxiv.org/abs/2405.13963