Crowding alters F-actin secondary structure and hydration

02 May 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Actin, a key component of the cytoskeleton in eukaryotic cells, plays a crucial role in regulating cell morphology and transport. The morphology, mechanical, and biochemical properties of these filaments and bundles are determined by their monomer structure and by protein-protein contacts. Crowded environments are known to organize filaments into bundles. However, less is known how crowding and bundling affect the structure of F-actin. Here, we employed two-dimensional infrared (2D IR) spectroscopy and structure-based spectral calculations to investigate the morphology-dependent secondary-structure and local environments in filaments and weakly or strongly bundled networks. The results indicate that actin undergo secondary structural changes upon bundling, resulting in a decrease in beta-sheet and increase in the loop conformations. Moreover, strongly bundled networks experience a decrease in backbone solvent exposure, with relatively low perturbation of alpha-helix and the beta-sheet nearly ``locked" in buried positions. Similar changes are observed in the loops, which become less hydrated but exhibit a dynamic environment. In summary, our study provides insights into the structure and structure-dependent local environment of actin biopolymers under morphology control by PEG, emphasizing the significance of loop structure as a critical player in actin network morphology and stability.

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.