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Liquid but durable: molecular dynamics simulations explain the unique properties of archaeal-like membranes.

Chugunov AO, Volynsky PE, Krylov NA, Boldyrev IA, Efremov RG - Sci Rep (2014)

Bottom Line: These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature.We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells.This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

View Article: PubMed Central - PubMed

Affiliation: M.M. Shemyakin &Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997.

ABSTRACT
Archaeal plasma membranes appear to be extremely durable and almost impermeable to water and ions, in contrast to the membranes of Bacteria and Eucaryota. Additionally, they remain liquid within a temperature range of 0-100°C. These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature. In this work, we use molecular dynamics simulations to assess at the atomistic level the structure and dynamics of a series of model archaeal membranes with lipids that have tetraether chemical nature and "branched" hydrophobic tails. We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells. This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

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Chemical structures of lipid molecules in this MD-study.Five upper molecules are mimetics of archaeal bolalipids. The “core” structure represented by the m0r0 molecule consists of two straight O-linked C32 alkyl chains, connected to an archaeal-type glycerol molecule with ether bonds. In all cases, the hydrophilic heads are phosphatidylcholines. Other mimetics (m0r2, m2r0, m6r2 and m8r0) have different numbers of branching modifications of the hydrophobic core: methyl groups (designated as “m” in mimetic codes) and cyclopentane rings (designated as “r”). The lower row contains dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC), which were chosen for comparison.
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f1: Chemical structures of lipid molecules in this MD-study.Five upper molecules are mimetics of archaeal bolalipids. The “core” structure represented by the m0r0 molecule consists of two straight O-linked C32 alkyl chains, connected to an archaeal-type glycerol molecule with ether bonds. In all cases, the hydrophilic heads are phosphatidylcholines. Other mimetics (m0r2, m2r0, m6r2 and m8r0) have different numbers of branching modifications of the hydrophobic core: methyl groups (designated as “m” in mimetic codes) and cyclopentane rings (designated as “r”). The lower row contains dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC), which were chosen for comparison.

Mentions: To assess the effect of branching groups of bolalipids' hydrophobic tails on the structural, dynamic and hydrophobic organization of the model archaeal membranes in a systematic manner, we simulated several hydrated monolayers composed of bolalipids, with hydrophobic tails gradually varying from straight C32 alkyl chains to archaeal-like C40 methyl-branched isoprenoid chains. The glycerol backbone stereochemistry and the way in which the hydrophobic tails are connected were archaeal-like, whereas polar heads were phosphatidylcholines (PC) — the most common variant in Eucaryota. PC was chosen in order to focus primarily on the effect of the chemical structure of the hydrophobic tails and compare the results with those obtained for common PC-based phospholipids — dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC). Five mimetics of bolalipids were selected for the computational analysis. They differed by the number and chemical nature of the branching groups: methyls (m) and cyclopentane rings (r). The “core” mimetic does not contain any modifications and hereinafter is referred to as m0r0 (this one is the most “artificial”). M8r0 and m6r2 mimetics have eight branching modifications in each tail (eight methyl groups and six methyl groups plus two rings, respectively) (these two are the most “native-like”). Besides these, two “intermediate” mimetics, m0r2 and m2r0, which contain two branching modifications per tail (two rings or two methyls, respectively), were chosen. The chemical structure of all five mimetics (along with DPPC and POPC) is shown in Fig. 1.


Liquid but durable: molecular dynamics simulations explain the unique properties of archaeal-like membranes.

Chugunov AO, Volynsky PE, Krylov NA, Boldyrev IA, Efremov RG - Sci Rep (2014)

Chemical structures of lipid molecules in this MD-study.Five upper molecules are mimetics of archaeal bolalipids. The “core” structure represented by the m0r0 molecule consists of two straight O-linked C32 alkyl chains, connected to an archaeal-type glycerol molecule with ether bonds. In all cases, the hydrophilic heads are phosphatidylcholines. Other mimetics (m0r2, m2r0, m6r2 and m8r0) have different numbers of branching modifications of the hydrophobic core: methyl groups (designated as “m” in mimetic codes) and cyclopentane rings (designated as “r”). The lower row contains dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC), which were chosen for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4264030&req=5

f1: Chemical structures of lipid molecules in this MD-study.Five upper molecules are mimetics of archaeal bolalipids. The “core” structure represented by the m0r0 molecule consists of two straight O-linked C32 alkyl chains, connected to an archaeal-type glycerol molecule with ether bonds. In all cases, the hydrophilic heads are phosphatidylcholines. Other mimetics (m0r2, m2r0, m6r2 and m8r0) have different numbers of branching modifications of the hydrophobic core: methyl groups (designated as “m” in mimetic codes) and cyclopentane rings (designated as “r”). The lower row contains dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC), which were chosen for comparison.
Mentions: To assess the effect of branching groups of bolalipids' hydrophobic tails on the structural, dynamic and hydrophobic organization of the model archaeal membranes in a systematic manner, we simulated several hydrated monolayers composed of bolalipids, with hydrophobic tails gradually varying from straight C32 alkyl chains to archaeal-like C40 methyl-branched isoprenoid chains. The glycerol backbone stereochemistry and the way in which the hydrophobic tails are connected were archaeal-like, whereas polar heads were phosphatidylcholines (PC) — the most common variant in Eucaryota. PC was chosen in order to focus primarily on the effect of the chemical structure of the hydrophobic tails and compare the results with those obtained for common PC-based phospholipids — dipalmitoylphosphatidylcholine (DPPC) and palmitoyloleylphosphatidylcholine (POPC). Five mimetics of bolalipids were selected for the computational analysis. They differed by the number and chemical nature of the branching groups: methyls (m) and cyclopentane rings (r). The “core” mimetic does not contain any modifications and hereinafter is referred to as m0r0 (this one is the most “artificial”). M8r0 and m6r2 mimetics have eight branching modifications in each tail (eight methyl groups and six methyl groups plus two rings, respectively) (these two are the most “native-like”). Besides these, two “intermediate” mimetics, m0r2 and m2r0, which contain two branching modifications per tail (two rings or two methyls, respectively), were chosen. The chemical structure of all five mimetics (along with DPPC and POPC) is shown in Fig. 1.

Bottom Line: These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature.We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells.This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

View Article: PubMed Central - PubMed

Affiliation: M.M. Shemyakin &Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997.

ABSTRACT
Archaeal plasma membranes appear to be extremely durable and almost impermeable to water and ions, in contrast to the membranes of Bacteria and Eucaryota. Additionally, they remain liquid within a temperature range of 0-100°C. These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature. In this work, we use molecular dynamics simulations to assess at the atomistic level the structure and dynamics of a series of model archaeal membranes with lipids that have tetraether chemical nature and "branched" hydrophobic tails. We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells. This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

Show MeSH