Molecular Dynamics Simulations of the Lipid Bilayer Edge

Abstract

Phospholipid bilayers have been intensively studied by molecular dynamics (MD) simulation in recent years. The properties of bilayer edges are important in determining the structure and stability of pores formed in vesicles and biomembranes. In this work, we use molecular dynamics simulation to investigate the structure, dynamics, and line tension of the edges of bilayer ribbons composed of pure dimyristoylphosphatidylcholine (DMPC) or palmitoyl-oleoylphosphatidylethanolamine (POPE). As expected, we observe a significant reorganization of lipids at and near the edges. The treatment of electrostatic effects is shown to have a qualitative impact on the structure and stability of the edge, and significant differences are observed in the dynamics and structure of edges formed by DMPC and palmitoyl-oleoylphosphatidylethanolamine. From the pressure anisotropy in the simulation box, we calculate a line tension of approximately 10-30 pN for the DMPC edge, in qualitative agreement with experimental estimates for similar lipids.

Long-timescale motions in glycerol-monopalmitate lipid bilayers investigated using molecular dynamics simulation

“…The parameters and depend on the dominant phase during the simulation, on the extent of hydration and on the possible presence of CSLs. The incomplete events (incursion and excursion) appear more often than the complete events (flip and hop), consistent with the behavior of phospholipids at bilayer edges [103]. It is important to stress that incursions are only defined by the passage of a headgroup in the bilayer midplane (irrespective of the tail position) and excursions by the passage of a tail methyl group at the box wall in the aqueous region (irrespective of the headgroup position).…”

Linking Phospholipase Mobility to Activity by Single‐Molecule Wide‐Field Microscopy

“…This confirms previous AFM studies and is easily rationalised given that penetration of the enzyme into the lipid layer is much easier at defect regions where molecular packing is less dense. [48,49] This work improves upon existing AFM studies as the perturbation of the phospholipid bilayers by contact with the AFM probe is avoided and better time resolution can be achieved (milliseconds for wide-field imaging versus seconds for AFM measurements).…”

Elastic properties and line tension of self-assembled bilayer membranes

“…The line tension has also been determined from computer simulations of various atomistic or coarse-grained models, both for mechanically stretched membranes [36][37][38][39][40] and tensionless membranes [41][42][43][44]. In comparison, theoretical studies of the line tension are scarce [45,46].…”