title: Cyclo-hexa-peptides at the water/cyclohexane interface: a molecular dynamics simulation.
abstract: Molecular dynamic (MD) simulations have been performed to study the behaviors of ten kinds of cyclo-hexa-peptides (CHPs) composed of amino acids with the diverse hydrophilic/hydrophobic side chains at the water/cyclohexane interface. All the CHPs take the "horse-saddle" conformations at the interface and the hydrophilicity/hydrophobicity of the side chains influences the backbones' structural deformations. The orientations and distributions of the CHPs at the interface and the differences of interaction energies (ΔΔE) between the CHPs and the two liquid phases have been determined. RDF analysis shows that the H-bonds were formed between the O(C) atoms of the CHPs' backbones and H(w) atoms of water molecules. N atoms of the CHPs' backbones formed the H-bonds or van der Waals interactions with the water solvent. It was found that there is a parallel relationship between ΔΔE and the lateral diffusion coefficients (D                 (                   xy                 )) of the CHPs at the interface. The movements of water molecules close to the interface are confined to some extent, indicating that the dynamics of the CHPs and interfacial water molecules are strongly coupled.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Cen
authors.forename: Jian Fen
authors.initials: JF
authors.lastname: Fan
authors.forename: Dong Yan
authors.initials: DY
authors.lastname: Liu
authors.forename: Xue Zeng
authors.initials: XZ
authors.lastname: Song
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Wei Qun
authors.initials: WQ
authors.lastname: Zhou
authors.forename: He Ming
authors.initials: HM
authors.lastname: Xiao
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry*; D004583:Electrons; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D056004:Molecular Dynamics Simulation; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D055672:Static Electricity; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D003510:Cyclohexanes; D010456:Peptides, Cyclic; D014867:Water; C506365:Cyclohexane