Issue 12, 2017

Molecular dynamics simulations of β2-microglobulin interaction with hydrophobic surfaces

Abstract

Hydrophobic surfaces are known to adsorb and unfold proteins, a process that has been studied only for a few proteins. Here we address the interaction of β2-microglobulin, a paradigmatic protein for the study of amyloidogenesis, with hydrophobic surfaces. A system with 27 copies of the protein surrounded by a model cubic hydrophobic box is studied by implicit solvent molecular dynamics simulations. Most proteins adsorb on the walls of the box without major distortions in local geometry, whereas free molecules maintain proper structures and fluctuations as observed in explicit solvent molecular dynamics simulations. The major conclusions from the simulations are as follows: (i) the adopted implicit solvent model is adequate to describe protein dynamics and thermodynamics; (ii) adsorption occurs readily and is irreversible on the simulated timescale; (iii) the regions most involved in molecular encounters and stable interactions with the walls are the same as those that are important in protein–protein and protein–nanoparticle interactions; (iv) unfolding following adsorption occurs at regions found to be flexible by both experiments and simulations; (v) thermodynamic analysis suggests a very large contribution from van der Waals interactions, whereas unfavorable electrostatic interactions are not found to contribute much to adsorption energy. Surfaces with different degrees of hydrophobicity may occur in vivo. Our simulations show that adsorption is a fast and irreversible process which is accompanied by partial unfolding. The results and the thermodynamic analysis presented here are consistent with and rationalize previous experimental work.

Graphical abstract: Molecular dynamics simulations of β2-microglobulin interaction with hydrophobic surfaces

Article information

Article type
Paper
Submitted
26 Jul 2017
Accepted
09 Oct 2017
First published
09 Oct 2017

Mol. BioSyst., 2017,13, 2625-2637

Molecular dynamics simulations of β2-microglobulin interaction with hydrophobic surfaces

C. J. Dongmo Foumthuim, A. Corazza, G. Esposito and F. Fogolari, Mol. BioSyst., 2017, 13, 2625 DOI: 10.1039/C7MB00464H

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