The effect of hydronium ions on the structure of phospholipid membranes

This work seeks to identify the mechanisms by which hydronium ions (H 3 O + ) modulate the structure of phospholipid bilayers by studying the interactions of H 3 O + with phospholipids at the molecular level. For this, we carried out multiple microsecond-long unrestrained molecular dynamics (MD) sim...

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Bibliographic Details
Main Authors: Deplazes, Evelyne, Poger, D., Cornell, B., Cranfield, C.
Format: Journal Article
Published: R S C Publications 2017
Online Access:http://hdl.handle.net/20.500.11937/60740
Description
Summary:This work seeks to identify the mechanisms by which hydronium ions (H 3 O + ) modulate the structure of phospholipid bilayers by studying the interactions of H 3 O + with phospholipids at the molecular level. For this, we carried out multiple microsecond-long unrestrained molecular dynamics (MD) simulations of a POPC bilayer at different H 3 O + concentrations. The results show that H 3 O + accumulates at the membrane surface where it displaces water and forms strong and long-lived hydrogen bonds with the phosphate and carbonyl oxygens in phospholipids. This results in a concentration-dependent reduction of the area per lipid and an increase in bilayer thickness. This study provides an important molecular-level insight into the mechanism of how H 3 O + modulates the structure of biological membranes and is a critical step towards a better understanding of the effect of low pH on mammalian and bacterial membranes.