title: Water Hydrogen-Bonding Network Structure and Dynamics at Phospholipid Multibilayer Surface: Femtosecond Mid-IR Pump-Probe Spectroscopy.
abstract: The water hydrogen-bonding network at a lipid bilayer surface is crucial to understanding membrane structures and its functional activities. With a phospholipid multibilayer mimicking a biological membrane, we study the temperature dependence of water hydrogen-bonding structure, distribution, and dynamics at a lipid multibilayer surface using femtosecond mid-IR pump-probe spectroscopy. We observe two distinguished vibrational lifetime components. The fast component (0.6 ps) is associated with water interacting with a phosphate part, whereas the slow component (1.9 ps) is with bulk-like choline-associated water. With increasing temperature, the vibrational lifetime of phosphate-associated water remains constant though its relative fraction dramatically increases. The OD stretch vibrational lifetime of choline-bound water slows down in a sigmoidal fashion with respect to temperature, indicating a noticeable change of the water environment upon the phase transition. The water structure and dynamics are thus shown to be in quantitative correlation with the structural change of liquid multibilayer upon the gel-to-liquid crystal phase transition.
authors: Achintya
authors: A
authors: Kundu
authors: Bartosz
authors: B
authors: Błasiak
authors: Joon-Hyung
authors: JH
authors: Lim
authors: Department of Chemistry, Chung-Ang University , Seoul 156-756, Republic of Korea.
authors: Kyungwon
authors: K
authors: Kwak
authors: Minhaeng
authors: M
authors: Cho
mesh_terms: D006860:Hydrogen Bonding; D008051:Lipid Bilayers / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods*; D014867:Water / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D014867:Water