Density fluctuations in saturated phospholipid bilayers increase as the acyl-chain length decreases

• Published in: Biophysical journal Vol. 58; no. 5; pp. 1099 - 1107
• Main Authors: Ipsen, J.H., Jørgensen, K., Mouritsen, O.G.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.11.1990; Biophysical Society
• Subjects: Artificial membranes and reconstituted systems; Biological and medical sciences; Biophysical Phenomena; Biophysics; computer simulations; Fundamental and applied biological sciences. Psychology; Lipid Bilayers - chemistry; Membrane physicochemistry; Models, Chemical; Molecular biophysics; Molecular Conformation; Molecular Structure; Monte Carlo Method; Phospholipids - chemistry; Thermodynamics; Computer simulation; Specific gravity; Chain length; Phospholipid; Ion transport; Artificial membrane; Models; Fatty acids; Bilayer; Phase transitions
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/S0006-3495(90)82452-8

A systematic computer simulation study is conducted for a model of the main phase transition of fully hydrated saturated diacyl phosphatidylcholine bilayers (DMPC, DPPC, and DSPC). With particular focus on the fluctuation effects on the thermal properties in the transition region, the study yields data for the specific heat, the lateral compressibility, and the lipid-domain size distribution. Via a simple model assumption the transmembrane passive ion permeability is derived from the lipid-domain interfacial measure. A comparative analysis of the various data shows, in agreement with a number of experiments, that the lateral density fluctuations and hence the response functions increase as the acyl-chain length is decreased.