Stacks of monogalactolipid bilayers can transform into a lattice of water channels

Jakub Hryc; Michal Markiewicz; Marta Pasenkiewicz-Gierula

doi:10.1016/j.isci.2023.107863

Stacks of monogalactolipid bilayers can transform into a lattice of water channels

iScience. 2023 Sep 9;26(10):107863. doi: 10.1016/j.isci.2023.107863. eCollection 2023 Oct 20.

Authors

Jakub Hryc¹, Michal Markiewicz¹, Marta Pasenkiewicz-Gierula¹

Affiliation

¹ Department of Computational Biophysics and Bioinformatics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland.

Abstract

The lipid matrix of thylakoid membranes is a lamellar bilayer, but under a certain condition it can convert locally into a nonlamellar structure. This is possible because one of the main membrane lipids, MGDG, promotes the formation of an inverse hexagonal phase. Here, the spontaneous transformation of aligned hydrated MGDG bilayers into nonlamellar structures is investigated using all-atom molecular dynamics simulation. Previous studies have demonstrated that MGDG polar head groups connect vertically across the interface. In this study, the evolution of the system's initial structure into a lattice of water channels and contacted surfaces created by numerous vertical MGDG connections depended on the width of the hydrating water layers. These widths controlled the bilayers' ability to bend, which was a prerequisite for channel formation. Locally, an intensive exchange of MGDG molecules between apposing bilayer leaflets occurred, although a stable semi-toroidal stalk did not develop.

Keywords: Biophysics; Membrane architecture; Structural biology.