title: A molecular dynamics study of the stoichiometric complex formed by poly (alpha, L-glutamate) and octyltrimethylammonium ions in chloroform solution.
abstract: We present a molecular dynamics simulation at 300 K in explicit solvent environment of chloroform of the stoichiometric complex formed by poly(alpha,L-glutamate) and octyltrimethylammonium ions. We observed that the alpha-helix conformation of the polypeptide chain remains stable during a 2-ns run. The surfactant ions predominantly adopted an extended conformation that is stabilized by favorable interactions with the organic solvent. Analysis of the organization of the surfactant with respect to the polypeptide chain indicated that each octyltrimethylammonium cation was preferentially bound to more than one carboxylate group. It was found that the most populated arrangement was that with the surfactant cations interacting with two carboxylate groups simultaneously.
authors.affiliation: Department d'Enginyeria Química, E. T. S. d'Enginyers Industrials de Barcelona, Universitat Politècnica de Catalunya, Diagonal 647, Barcelona E-08028, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Zanuy
authors.forename: Carlos
authors.initials: C
authors.lastname: Alemán
authors.forename: Sebastián
authors.initials: S
authors.lastname: Muñoz-Guerra
mesh_terms: D002412:Cations; D002725:Chloroform / Q000737:chemistry*; D002942:Circular Dichroism; D003198:Computer Simulation; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008958:Models, Molecular; D011099:Polyglutamic Acid / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000378:metabolism; D012996:Solutions; D012997:Solvents / Q000737:chemistry*; D055672:Static Electricity; D013501:Surface-Active Agents / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D002412:Cations; D046911:Macromolecular Substances; D000644:Quaternary Ammonium Compounds; D012996:Solutions; D012997:Solvents; D013501:Surface-Active Agents; C042006:octyltrimethylammonium; D011099:Polyglutamic Acid; D002725:Chloroform