title: The Partitioning of Small Aromatic Molecules to Air-Water and Phospholipid Interfaces Mediated by Non-Hydrophobic Interactions.
abstract: Phenylalanine has an important role both in normal biological function and in disease states such as phenylketonuria (PKU) and amyloid fibril diseases. Two crucial aspects of phenylalanine behavior in biological systems are its preferential partitioning into membranes and its propensity to cluster. In order to examine the intermolecular interactions that give rise to this behavior, the surface partitioning behavior was investigated for a series of molecules structurally related to phenylalanine (phenylglycine, phenylacetic acid, and tyrosine) both experimentally and by molecular dynamics simulations. Surface tension measurements were performed over time for aromatic solutions both in the presence and in the absence of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) monolayer films, which functioned as simple model membranes. The observed trends in surface activity defy simple predictions based on solubility and hydrophobicity. The possibility of clustering is investigated through a combination of Langmuir trough, nuclear magnetic resonance (NMR), fluorescence self-quenching, and mass spectroscopy measurements. It is concluded that clustering does not occur in solution to a significant extent for these molecules, but interfacial clustering is likely. An explanation for observed trends in surface activity is presented on the basis of cluster stability and molecular conformational flexibility.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado at Boulder , UCB 215, Boulder, Colorado 80309, United States.|Cooperative Institute for Research In Environmental Sciences, University of Colorado Boulder , UCV 215, Boulder, Colorado 80309, United States.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Perkins
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, 18223 Prague 8, Czech Republic.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kukharchuk
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic.
authors.forename: Pauline
authors.initials: P
authors.lastname: Delcroix
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado at Boulder , UCB 215, Boulder, Colorado 80309, United States.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Shoemaker
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic , Flemingovo nám. 2, 16610 Prague 6, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Roeselová
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 3, 18223 Prague 8, Czech Republic.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Cwiklik
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado at Boulder , UCB 215, Boulder, Colorado 80309, United States.|Cooperative Institute for Research In Environmental Sciences, University of Colorado Boulder , UCV 215, Boulder, Colorado 80309, United States.
authors.forename: Veronica
authors.initials: V
authors.lastname: Vaida
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000388:Air; D016000:Cluster Analysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D056004:Molecular Dynamics Simulation; D010649:Phenylalanine / Q000737:chemistry*; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D014443:Tyrosine / Q000737:chemistry; D053835:Unilamellar Liposomes / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D053835:Unilamellar Liposomes; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; D014443:Tyrosine; D010649:Phenylalanine