Structure and stability of self-assembled actin-lysozyme complexes in salty water

TL;DR

This study investigates the formation and stability of actin-lysozyme complexes in salty water, revealing stable hexagonal arrangements maintained by salt redistribution, combining experimental and simulation approaches.

Contribution

It provides new insights into the structural organization and salt tolerance of actin-lysozyme complexes through combined experimental and molecular dynamics methods.

Findings

Actin-lysozyme complexes form hexagonally-coordinated structures.

Complexes remain stable despite high salt concentrations.

Salt redistribution explains the stability in salty environments.

Abstract

Interactions between actin, an anionic polyelectrolyte, and lysozyme, a cationic globular protein, have been examined using a combination of synchrotron small-angle x-ray scattering and molecular dynamics simulations. Lysozyme initially bridges pairs of actin filaments, which relax into hexagonally-coordinated columnar complexes comprised of actin held together by incommensurate one-dimensional close-packed arrays of lysozyme macroions. These complexes are found to be stable even in the presence of significant concentrations of monovalent salt, which is quantitatively explained from a redistribution of salt between the condensed and the aqueous phases.