title: Peptide encapsulation regulated by the geometry of carbon nanotubes.
abstract: In this work the encapsulation of an α-helical peptide in single carbon nanotubes (CNTs) with similar diameter and length but different geometry (armchair and zigzag) was investigated through molecular dynamics simulations and free energy calculations. Our simulation results showed that in vacuo it makes no evident difference whether the investigated peptide is encapsulated in armchair or zigzag CNTs; however, in aqueous solution the armchair CNT encapsulates the peptide remarkably easier than the zigzag CNT does. A detailed analysis revealed that the equilibrium conformation of the water molecules inside the CNTs with varying geometry mediates the peptide encapsulation. It suggests that the water molecules play an important role in regulating behaviors of biomolecules in bio-systems. Then the impact of the CNT geometry on the conformational changes of the confined peptide was studied. Analyses of secondary structures showed the α-helix of the peptide could be better maintained in the zigzag CNT.
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Zhi-Sen
authors.initials: ZS
authors.lastname: Zhang
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Liang
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China. Electronic address: liuyingch@zju.edu.cn.
authors.forename: Ying-Chun
authors.initials: YC
authors.lastname: Liu
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.affiliation: Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou 310027, PR China. Electronic address: qiwang@zju.edu.cn.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D056004:Molecular Dynamics Simulation; D037742:Nanotubes, Carbon; D010455:Peptides / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D037742:Nanotubes, Carbon; D010455:Peptides
keywords: Geometry of CNTs; Interfacial water mediation; Peptide encapsulation; Umbrella sampling