Nitrous Oxide Vibrational Energy Relaxation Is a Probe of Interfacial Water in Lipid Bilayers

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• 作者：Logan R. Chieffo ; Jeffrey T. Shattuck ; Eric Pinnick ; Jason J. Amsden ; M. K. Hong ; Feng Wang ; Shyamsunder Erramilli ; Lawrence D. Ziegler
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：October 9, 2008
• 年：2008
• 卷：112
• 期：40
• 页码：12776-12782
• 全文大小：317K
• 年卷期：v.112,no.40(October 9, 2008)
• ISSN：1520-5207

文摘

Ultrafast infrared spectroscopy of N₂O is shown to be a sensitive probe of hydrophobic and aqueous sites in lipid bilayers. Distinct rates of VER of the ν₃ antisymmetric stretching mode of N₂O can be distinguished for N₂O solvated in the acyl tail, interfacial water, and bulk water regions of hydrated dioleoylphosphatidylcholine (DOPC) bilayers. The lifetime of the interfacial N₂O population is hydration-dependent. This effect is attributed to changes in the density of intermolecular states resonant with the ν₃ band (∼2230 cm⁻¹) resulting from oriented interfacial water molecules near the lipid phosphate. Thus, the N₂O 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.