A molecular dynamics study of an archaeal tetraether lipid membrane: Comparison with a dipalmitoylphosphatidylcholine lipid bilayer

Abstract

Molecular dynamics simulations of an archaeal membrane made up of bipolar tetraether lipids and a dipalmitoylphosphatidylcholine (DPPC) lipid membrane were performed and compared for the first time. The simulated archaeal membrane consists of a pure monolayer of asymmetrical lipids, analogous to the main polar lipid [MPL; Swain, M., Brisson, J.-R., Sprott, G.D., Cooper, F.P., and Patel, G.B., (1997) Identification of beta-L-Gulose as the Sugar Moiety of the Main Polar Lipid of Thermoplasma acidophilum, Biochim. Biophys. Acta 1345, 56-64] found in T. acidophilum, an extremophile archaeal organism. This simulated membrane lipid contains two cyclopentane rings located on one of the two aliphatic chains of the lipid. The archaeal membrane is simulated at 62degreesC, slightly above the optimal growth temperature of T. acidophilum. We compared the organization of this tetraether lipid monolayer with a DPPC bilayer simulated at 50degreesC, both of them being modeled in a partially hydrated state. Our results assess the singularity of the tetraether lipid organization, in particular the influence of the spanning structure on the molecular ordering within the archaeal membrane.

Structural characterization of liposomes made of diether archaeal lipids and dipalmitoyl-L-α-phosphatidylcholine

“…Based on our results presented here, it is likely that with respect to their permeability, fluidity and thermal stability, binary lipid mixtures of diether C 25,25 lipids and DPPC behave similarly as tetraether lipid and DPPC mixtures, although they are structurally different [9,10]. The model tetraether lipid membrane can be defined as an assembly of tightly packed molecules [27].…”

Archaebacterial bipolar tetraether lipids: Physico-chemical and membrane properties

“…Molecular dynamic (MD) simulations on membranes composed of an analog of the main polar lipids (MPL) from T. acidophilum seem to contradict the 31 P NMR results (Nicolas, 2005) because the simulation showed that, at temperatures a few degrees above the growth temperature, the MPL analog does not exhibit a significant lateral diffusion, at least not at the time scale of the simulation (Nicolas, 2005). However, the MD simulations did show higher molecular order for MPL-like lipids than for conventional diester lipids (Nicolas, 2005).…”

Biological Membranes in Extreme Conditions: Anionic Tetraether Lipid Membranes and Their Interactions with Sodium and Potassium

“…Several other models of tetraether membranes were developed. [16][17][18][19][20][21] We studied di-and tetra-ether membranes by MD simulations, where the negative charge on tetraether membranes from S. acidocaldarius was neutralized by counterions. 22 Analysis of the simulations revealed that the size of the counterions affected the physical properties of the membranes.…”