Minimal lattice model of lipid membranes with liquid-ordered domains

Mixtures of lipids and cholesterol are commonly used as model systems for studying the formation of liquid-ordered (L_{o}) domains in heterogeneous biological membranes. The simplest model system exhibiting coexistence between L_{o} domains and a liquid-disordered (L_{d}) matrix is that of a binary...

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Main Authors: Tanmoy Sarkar, Oded Farago
Format: Article
Language:English
Published: American Physical Society 2021-11-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.3.L042030
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author Tanmoy Sarkar
Oded Farago
author_facet Tanmoy Sarkar
Oded Farago
author_sort Tanmoy Sarkar
collection DOAJ
description Mixtures of lipids and cholesterol are commonly used as model systems for studying the formation of liquid-ordered (L_{o}) domains in heterogeneous biological membranes. The simplest model system exhibiting coexistence between L_{o} domains and a liquid-disordered (L_{d}) matrix is that of a binary mixture of saturated lipids such as DPPC and cholesterol (Chol). DPPC/Chol mixtures have been investigated for decades both experimentally, theoretically, and recently also by means of atomistic simulations. Here, we present a minimal lattice model that captures the correct behavior of this mixture across multiple scales. On the macroscopic scales, we present simulation results of mixtures of thousands of lipids and Chol molecules which show excellent agreement with the phase diagram of the system. The simulations are conducted on timescales of hundreds of microseconds and show the morphologies and dynamics of the domains. On the molecular scales, the simulations reveal local structures similar to those recently seen in atomistic simulations, including the formation of gel-like nanodomains (∼1–10 nm) within larger Chol-rich L_{o} domains (∼10–100 nm). The observed multiscale behavior is related to the tendency of Chol to induce ordering of acyl chains on the one hand, and disrupt their packing with each other, on the other hand.
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spelling doaj.art-f6d1d8fc2a554cb8bc0329ffd0aff6d72024-04-12T17:15:49ZengAmerican Physical SocietyPhysical Review Research2643-15642021-11-0134L04203010.1103/PhysRevResearch.3.L042030Minimal lattice model of lipid membranes with liquid-ordered domainsTanmoy SarkarOded FaragoMixtures of lipids and cholesterol are commonly used as model systems for studying the formation of liquid-ordered (L_{o}) domains in heterogeneous biological membranes. The simplest model system exhibiting coexistence between L_{o} domains and a liquid-disordered (L_{d}) matrix is that of a binary mixture of saturated lipids such as DPPC and cholesterol (Chol). DPPC/Chol mixtures have been investigated for decades both experimentally, theoretically, and recently also by means of atomistic simulations. Here, we present a minimal lattice model that captures the correct behavior of this mixture across multiple scales. On the macroscopic scales, we present simulation results of mixtures of thousands of lipids and Chol molecules which show excellent agreement with the phase diagram of the system. The simulations are conducted on timescales of hundreds of microseconds and show the morphologies and dynamics of the domains. On the molecular scales, the simulations reveal local structures similar to those recently seen in atomistic simulations, including the formation of gel-like nanodomains (∼1–10 nm) within larger Chol-rich L_{o} domains (∼10–100 nm). The observed multiscale behavior is related to the tendency of Chol to induce ordering of acyl chains on the one hand, and disrupt their packing with each other, on the other hand.http://doi.org/10.1103/PhysRevResearch.3.L042030
spellingShingle Tanmoy Sarkar
Oded Farago
Minimal lattice model of lipid membranes with liquid-ordered domains
Physical Review Research
title Minimal lattice model of lipid membranes with liquid-ordered domains
title_full Minimal lattice model of lipid membranes with liquid-ordered domains
title_fullStr Minimal lattice model of lipid membranes with liquid-ordered domains
title_full_unstemmed Minimal lattice model of lipid membranes with liquid-ordered domains
title_short Minimal lattice model of lipid membranes with liquid-ordered domains
title_sort minimal lattice model of lipid membranes with liquid ordered domains
url http://doi.org/10.1103/PhysRevResearch.3.L042030
work_keys_str_mv AT tanmoysarkar minimallatticemodeloflipidmembraneswithliquidordereddomains
AT odedfarago minimallatticemodeloflipidmembraneswithliquidordereddomains