title: Nitrous oxide vibrational energy relaxation is a probe of interfacial water in lipid bilayers.
abstract: Ultrafast infrared spectroscopy of N 2O is shown to be a sensitive probe of hydrophobic and aqueous sites in lipid bilayers. Distinct rates of VER of the nu 3 antisymmetric stretching mode of N 2O can be distinguished for N 2O solvated in the acyl tail, interfacial water, and bulk water regions of hydrated dioleoylphosphatidylcholine (DOPC) bilayers. The lifetime of the interfacial N 2O population is hydration-dependent. This effect is attributed to changes in the density of intermolecular states resonant with the nu 3 band ( approximately 2230 cm (-1)) resulting from oriented interfacial water molecules near the lipid phosphate. Thus, the N 2O VER rate becomes a novel and experimentally convenient tool for reporting on the structure and dynamics of interfacial water in lipids and, potentially, in other biological systems.
authors.affiliation: Department of Chemistry, and Photonics Center, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA.
authors.forename: Logan R
authors.initials: LR
authors.lastname: Chieffo
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Shattuck
authors.forename: Eric
authors.initials: E
authors.lastname: Pinnick
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Amsden
authors.forename: M K
authors.initials: MK
authors.lastname: Hong
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Shyamsunder
authors.initials: S
authors.lastname: Erramilli
authors.forename: Lawrence D
authors.initials: LD
authors.lastname: Ziegler
mesh_terms: D003198:Computer Simulation; D008051:Lipid Bilayers / Q000737:chemistry*; D015335:Molecular Probes / Q000737:chemistry*; D009609:Nitrous Oxide / Q000737:chemistry*; D013053:Spectrophotometry; D014732:Vibration; D014867:Water / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D015335:Molecular Probes; D014867:Water; D009609:Nitrous Oxide