title: Understanding the phase behavior of coarse-grained model lipid bilayers through computational calorimetry.
abstract: We study the phase behavior of saturated lipids as a function of temperature and tail length for two coarse-grained models: the soft-repulsive model typically employed with dissipative particle dynamics (DPD) and the MARTINI model. We characterize the simulated transitions through changes in structural properties, and we introduce a computational method to monitor changes in enthalpy, as is done experimentally with differential scanning calorimetry. The lipid system experimentally presents four different bilayer phases - subgel, gel, ripple, and fluid - and the DPD model describes all of these phases structurally while MARTINI describes a single order-disorder transition between the gel and the fluid phases. Given both models' varying degrees of success in displaying accurate structural and thermodynamic signatures, there is an overall satisfying extent of agreement for the coarse-grained models. We also study the lipid dynamics displayed by these models for the various phases, discussing this dynamics with relation to fidelity to experiment and computational efficiency.
authors.affiliation: Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. jrodgers78@gmail.com
authors.forename: Jocelyn M
authors.initials: JM
authors.lastname: Rodgers
authors.forename: Jesper
authors.initials: J
authors.lastname: Sørensen
authors.forename: Frédérick J-M
authors.initials: FJ
authors.lastname: de Meyer
authors.forename: Birgit
authors.initials: B
authors.lastname: Schiøtt
authors.forename: Berend
authors.initials: B
authors.lastname: Smit
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods*; D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D008958:Models, Molecular; D044367:Phase Transition; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers