Bryant G, Pope J M, Wolfe J
School of Physics, University of New South Wales, Kensington, Australia.
Eur Biophys J. 1992;21(5):363-7. doi: 10.1007/BF00188350.
The reduction in spectral splitting, or motional narrowing, of the deuterium spectra of D2O/phospholipid mixtures near the main chain melting phase transition was studied for palmitoyloleoylphosphatidylcholine (POPC), palmitoyloleoylphosphatidylethanolamine (POPE) and equimolar mixtures of the two at 10% hydration. For POPC the splitting was about 1700 Hz in both the fluid and gel phases, dropping to zero near the phase transition (as reported previously). For POPE the splitting remained approximately constant above the phase transition. Below the phase transition the spectrum showed a single broad line whose linewidth varied between 100 Hz and 800 Hz. This was interpreted as being due to small domains of water within a weakly hydrated crystal. POPC:POPE (1:1) samples exhibited motional narrowing behaviour similar to that for POPC except that the splitting above the phase transition was approximately twice that below the transition. The relatively broad temperature range (approximately 20 K) of the transition is explained using a simple physical model involving lipid fluctuations near the phase transition.
研究了在10%水合度下，棕榈酰油酰磷脂酰胆碱（POPC）、棕榈酰油酰磷脂酰乙醇胺（POPE）以及二者等摩尔混合物在主链熔化相变附近D2O/磷脂混合物的氘谱的光谱分裂减小或运动变窄情况。对于POPC，在流体相和凝胶相中分裂约为1700 Hz，在相变附近降至零（如先前报道）。对于POPE，在相变以上分裂大致保持恒定。在相变以下，光谱显示出一条单一的宽线，其线宽在100 Hz至800 Hz之间变化。这被解释为是由于在弱水合晶体中存在小的水区域。POPC:POPE（1:1）样品表现出与POPC类似的运动变窄行为，只是相变以上的分裂约为相变以下的两倍。使用一个涉及相变附近脂质波动的简单物理模型解释了相对较宽的转变温度范围（约20 K）。
