title: Dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes.
abstract: Classical molecular dynamics simulations have been performed to investigate the dynamic behaviors and transport properties of ethanol molecules in transmembrane cyclic peptide nanotubes (CPNTs) with various radii, i.e., 8×(WL¯)n=3,4,5/POPE. The results show that ethanol molecules spontaneously fill the octa- and deca-CPNTs, but not the hexa-CPNT. In the octa-CPNT, ethanol molecules are trapped at individual gaps with their carbon skeletons perpendicular to the tube axis and hydroxyl groups towards the tube wall, forming a broken single-file chain. As the channel radius increases, ethanol molecules inside the deca-CPNT tend to form a tubular layer and the hydroxyl groups mainly stretch towards the tube axis. Computations of diffusion coefficients indicate that ethanol molecules in the octa-CPNT nearly lost their diffusion abilities, while those in the deca-CPNT diffuse as 4.5 times as in a (8, 8) carbon nanotube with a similar tube diameter. The osmotic and diffusion permeabilities (pf and pd, respectively) of the octa- and deca-CPNTs transporting ethanol were deduced for the first time. The distributions of the gauche and trans conformers of ethanol molecules in two CPNTs are quite similar, both with approximately 57% gauche conformers. The non-bonded interactions of channel ethanol with a CPNT wall and surrounding ethanol were explored. The potential of mean force elucidates the mechanism underlying the transporting characteristics of channel ethanol in a transmembrane CPNT.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
authors.forename: Jianfen
authors.initials: J
authors.lastname: Fan
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
authors.forename: Xiliang
authors.initials: X
authors.lastname: Yan
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D004058:Diffusion; D000431:Ethanol / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D043942:Nanotubes / Q000737:chemistry*; D009995:Osmosis; D010456:Peptides, Cyclic / Q000737:chemistry*; D010539:Permeability; D055672:Static Electricity
chemical_list: D010456:Peptides, Cyclic; D000431:Ethanol