Lipids: Phase Transitions

Koynova, Rumiana; Tenchov, Boris

doi:10.1002/9780470048672.wecb287

Cited by 7 publications

(8 citation statements)

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“…It assumes the existence of a lipid bilayer within which proteins are located in various ways. In this model, membrane lipids are in the liquid crystalline state and are laterally evenly distributed to form a homogeneous structure [38][39][40]. At the same time, however, it was known that cytoplasmic membranes must be laterally polarized in order to create a specific environment for some membrane proteins [41].…”

Section: Lipid Characteristics Of the Cytoplasmic Membranementioning

confidence: 99%

“…As the temperature increases, it transforms into the gel lamellar phase (L β ), a process called subtransition. As the temperature increases, L β melts and transforms into the L α phase, i.e., the liquid crystalline phase dominating in lipids [40]. This phase transition is known as the main phase transition.…”

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

“…L α under the influence of temperature increase undergoes mesomorphic transitions into non-lamellar liquid crystalline phases: hexagonal (H), micellar (M), and cubic (Q) [40,57]. The most common transition of this type is the transformation of L α to H II -the inverted hexagonal phase (Figure 4).…”

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

“…At the same time, local non-lamellar structures are desirable and play important roles, e.g., in fusion and separation of membranes [39,59]. The local presence of both H II and L β phases modulates the activity of membrane proteins [40]. It is this dynamic equilibrium that is completely destabilized during desiccation.…”

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

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Introduction to Bacterial Anhydrobiosis: A General Perspective and the Mechanisms of Desiccation-Associated Damage

Grzyb

Skłodowska

2022

Microorganisms

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Anhydrobiosis is the ability of selected organisms to lose almost all water and enter a state of reversible ametabolism. Such an organism dries up to a state of equilibrium with dry air. Unless special protective mechanisms exist, desiccation leads to damage, mainly to proteins, nucleic acids, and membrane lipids. A short historical outline of research on extreme dehydration of living organisms and the current state of research are presented. Terminological issues are outlined. The role of water in the cell and the mechanisms of damage occurring in the cell under the desiccation stress are briefly discussed. Particular attention was paid to damage to proteins, nucleic acids, and membrane lipids. Understanding the nature of the changes and damage associated with desiccation is essential for the study of desiccation-tolerance mechanisms and application research. Difficulties related to the definition of life and the limits of life in the scientific discussion, caused by the phenomenon of anhydrobiosis, were also indicated.

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Section: Lipid Characteristics Of the Cytoplasmic Membranementioning

confidence: 99%

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

Section: Phases and Phase Transitions Of Lipidsmentioning

confidence: 99%

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Introduction to Bacterial Anhydrobiosis: A General Perspective and the Mechanisms of Desiccation-Associated Damage

Grzyb

Skłodowska

2022

Microorganisms

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“…Phospholipids exhibit different phase behavior from inverse micelle to vesicle and micellar structures upon increase of the water content [24]. Among various self-assembled structures of the phospholipids, lamellar and inverted hexagonal phases are of particular importance in the formation of local domains within the membranes that lead to certain functions [25].…”

Section: Introductionmentioning

confidence: 99%

Implicit solvent systematic coarse-graining of dioleoylphosphatidylethanolamine lipids: From the inverted hexagonal to the bilayer structure

et al. 2019

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Lamellar and hexagonal lipid structures are of particular importance in the biological processes such as membrane fusion and budding. Atomistic simulations of formation of these phases and transitions between them are computationally prohibitive, hence development of coarse-grained models is an important part of the methodological development in this area. Here we apply systematic bottom-up coarse-graining to model different phase structures formed by 1,2-dioleoylphosphatidylethanolamine (DOPE) lipid molecules. We started from atomistic simulations of DOPE lipids in water carried out at two different water/lipid molar ratio corresponding to the lamellar L α and inverted hexagonal H II structures at low and high lipid concentrations respectively. The atomistic trajectories were mapped to coarse-grained trajectories, in which each lipid was represented by 14 coarse-grained sites. Then the inverse Monte Carlo method was used to compute the effective coarse-grained potentials which for the coarse-grain model reproduce the same structural properties as the atomistic simulations. The potentials derived from the low concentration atomistic simulation were only able to form a bilayer structure, while both L α and H II lipid phases were formed in simulations with potentials obtained at high concentration. The typical atomistic configurations of lipids at high concentration combine fragments of both lamellar and non-lamellar structures, that is reflected in the extracted coarse-grained potentials which become transferable and can form a wide range of structures including the inverted hexagonal, bilayer, tubule, vesicle and micellar structures.

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How Ethanolic Disinfectants Disintegrate Coronavirus Model Membranes: A Dissipative Particle Dynamics Simulation Study

Zhou

Das

et al. 2022

J. Chem. Theory Comput.

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We have developed dissipative particle dynamics models for pure dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and dimyristoylphosphatidylcholine (DMPC) as well as their binary and ternary mixed membranes, as coronavirus model membranes. The stabilities of pure and mixed membranes, surrounded by aqueous solutions containing up to 70 mol % ethanol (alcoholic disinfectants), have been investigated at room temperature. We found that aqueous solutions containing 5–10 mol % ethanol already have a significant weakening effect on the pure and mixed membranes. The magnitude of the effect depends on the membrane composition and the ethanol concentration. Ethanol permeabilizes the membrane, causing its lateral swelling and thickness shrinking and reducing the orientational order of the hydrocarbon tail of the bilayer. The free energy barrier for the permeation of ethanol in the bilayers is considerably reduced by the ethanol uptake. The rupture-critical ethanol concentrations causing the membrane failure are 20.7, 27.5, and 31.7 mol % in the aqueous phase surrounding pure DMPC, DOPC, and DPPC membranes, respectively. Characterizing the failure of lipid membranes by a machine-learning neural network framework, we found that all mixed binary and/or ternary membranes disrupt when immersed in an aqueous solution containing a rupture-critical ethanol concentration, ranging from 20.7 to 31.7 mol %, depending on the composition of the membrane; the DPPC-rich membranes are more intact, while the DMPC-rich membranes are least intact. Due to the tight packing of long, saturated hydrocarbon tails in DPPC, increasing the DPPC content of the mixed membrane increases its stability against the disinfectant. At high DPPC concentrations, where the DOPC and DMPC molecules are confined between the DPPC lipids, the ordered hydrocarbon tails of DPPC also induce order in the DOPC and DMPC molecules and, hence, stabilize the membrane more. Our simulations on pure and mixed membranes of a diversity of compositions reveal that a maximum ethanol concentration of 32 mol % (55 wt %) in the alcohol-based disinfectants is enough to disintegrate any membrane composed of these three lipids.

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Lipids: Phase Transitions

Cited by 7 publications

References 76 publications

Introduction to Bacterial Anhydrobiosis: A General Perspective and the Mechanisms of Desiccation-Associated Damage

Introduction to Bacterial Anhydrobiosis: A General Perspective and the Mechanisms of Desiccation-Associated Damage

Implicit solvent systematic coarse-graining of dioleoylphosphatidylethanolamine lipids: From the inverted hexagonal to the bilayer structure

How Ethanolic Disinfectants Disintegrate Coronavirus Model Membranes: A Dissipative Particle Dynamics Simulation Study

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