title: 500 picosecond molecular dynamics simulation of amphiphilic polypeptide Ac(LKKL)4 NHEt with 1,2 di-mysristoyl-sn-glycero-3-phosphorylcholine (DMPC) molecules.
abstract: Molecular dynamics (MD) simulation of the interaction between amphiphilic polypeptide Ac(LKKL)4NHEt and 4 DMPC (1,2 di-mysristoyl-sn-glycero-3-phosphorylcholine) molecules has been carried out at 310 K for 500 picoseconds (ps) using AMBER 4.0. Interaction energy and a number of conformational parameters are calculated for the subaveraged coordinates, using P-CURVES 3.1 and our MD trajectory analysis program ANALMD. No significant change in DMPC headgroup conformation was observed. However, the mobility of P atoms was found to be restricted. The chains were quite flexible and their flexibility increased towards the ends. They interacted amongst themselves. The polypeptide remained predominantly in alpha-helical conformation. Leu1 and Lys2 at the N terminus and Leu13 to Leu16 at C terminus assumed non helical conformation and were quite flexible. Average interaction energy between the polypeptide and DMPC molecules was found to be -151.828 kcal*mol-1. The main contributory factor was electrostatic interaction of Lys NH3+ groups with the DMPC phosphates. On an average one Lys chain interacted with 1.5 DMPC molecules. Central region of the polypeptide had better contact with DMPC molecules. A model for the fusogenic properties of the polypeptide is presented on the basis of MD results.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: D
authors.initials: D
authors.lastname: Gupta
authors.forename: V
authors.initials: V
authors.lastname: Kothekar
mesh_terms: D000595:Amino Acid Sequence; D002459:Cell Fusion; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013816:Thermodynamics
chemical_list: D046911:Macromolecular Substances; D010455:Peptides; D004134:Dimyristoylphosphatidylcholine