Nitrous oxide vibrational energy relaxation is a probe of interfacial water in lipid bilayers.
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.
Chieffo
Logan R
LR
Department of Chemistry, and Photonics Center, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA.
Shattuck
Jeffrey T
JT
Pinnick
Eric
E
Amsden
Jason J
JJ
Hong
M K
MK
Wang
Feng
F
Erramilli
Shyamsunder
S
Ziegler
Lawrence D
LD
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*
D008051:Lipid Bilayers; D015335:Molecular Probes; D014867:Water; D009609:Nitrous Oxide