PHOTOSYNTHETICA

Photosynthetica 2023, 61(4):441-450 | DOI: 10.32615/ps.2023.035

The impact of physiologically relevant temperatures on physical properties of thylakoid membranes: a molecular dynamics study

B. FEHÉR¹, I.K. VOETS¹, G. NAGY²

¹ Laboratory of Self-Organizing Soft Matter, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

² Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA

Thylakoid membranes are energy-converting membranes with a unique lipid composition. Though the membranes are primarily composed of proteins, their photosynthetic function is strongly influenced by the lipid constituents. Here we characterize, with molecular dynamics (MD) simulations, lipid bilayers with compositions representative of plant thylakoid membranes. We determine, in a wide range of temperatures, the physical parameters of the model membranes which are relevant for the photosynthetic function. We found a marked impact of temperature on membrane permeability due to a combination of increased compressibility and curvature of the membrane at elevated temperatures. With increasing temperatures, we observed increasingly smeared transmembrane density profiles of the membrane forming lipid headgroups predicting increased membrane flexibility. The diffusion coefficient of the lipids increased with temperature without apparent specificity for lipid species. Instead of a comprehensive experimental dataset in the relevant temperature range, we quantitatively compared and validated our MD results with MD simulations on a dipalmitoylphosphatidylcholine model system.

Additional key words: mechanical properties; molecular dynamics; permeability; thylakoid.

Received: July 10, 2023; Revised: August 30, 2023; Accepted: September 11, 2023; Prepublished online: October 10, 2023; Published: December 19, 2023  Show citation