Binder Hans
Interdisciplinary Centre for Bioinformatics, University of Leipzig, Leipzig, Germany.
Eur Biophys J. 2007 Apr;36(4-5):265-79. doi: 10.1007/s00249-006-0110-6. Epub 2006 Nov 7.
The ordering and H-bonding characteristics of the hydration water of the lipid 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) were studied using polarized infrared spectroscopy by varying either the temperature or the relative humidity of the ambient atmosphere of multibilayer samples. The OH-stretching band of lipid-bound water was interpreted by a simplified two-state model of well-structured, low density "network" water and of less-structured dense "multimer" water. The IR-spectroscopic data reflect a rather continuous change of the water properties with increasing distance from the membrane and with changing temperature. Network and multimer water distribute across the whole polar interphase with changing composition and orientation. Upon dehydration the fraction of network water increases from about 30 to 60%, a value which is similar to that in supercooled water at -25 degrees C. The highly ordered gel phase gives rise to an increased fraction of structured network water compared with the liquid crystalline phase. The IR order parameter shows that the water dipoles rearrange from a more parallel towards a more perpendicular orientation with respect to the membrane normal with progressive hydration.
通过改变多层样品周围大气的温度或相对湿度，利用偏振红外光谱研究了脂质1-棕榈酰-2-油酰磷脂酰胆碱（POPC）的水合水的排列和氢键特征。脂质结合水的OH伸缩带由结构良好、低密度的“网络”水和结构较少的致密“多聚体”水的简化二态模型解释。红外光谱数据反映了随着距膜距离的增加和温度的变化，水的性质发生相当连续的变化。网络水和多聚体水随着组成和取向的变化分布在整个极性界面上。脱水时，网络水的比例从约30%增加到60%，该值与-25℃过冷水中的值相似。与液晶相相比，高度有序的凝胶相导致结构化网络水的比例增加。红外序参数表明，随着水合作用的进行，水偶极子相对于膜法线从更平行的取向重新排列为更垂直的取向。
