Wittebort R J, Schmidt C F, Griffin R G
Biochemistry. 1981 Jul 7;20(14):4223-8. doi: 10.1021/bi00517a042.
The temperature dependence of the 13C NMR spectra of dipalmitoylphosphatidylcholine (DPPC) which has been 13C labeled at the carbonyl position of the sn-2 chain, 2-[1-13C]DPPC, is reported. In the L beta' phase an axially symmetric spectrum of 112-ppm breadth is observed, and this transforms to an isotropic-like line ((delta sigma) approximately 7 ppm) in the L alpha phase. In the intermediate P beta phase a temperature-dependent superposition of these spectra is observed, which suggests that this phase exhibits microscopic structural and dynamical properties of both the L beta' and L alpha phases. An analysis of the spectral line shapes leads to the conclusion that the appearance of the isotropic-like line in the P beta' phase is primarily due to a conformational change at the sn-2 carbonyl which is complete at the main transition. Increased rates of axial diffusion in the P beta' phase may contribute to the narrowing.
报道了在sn-2链的羰基位置进行13C标记的二棕榈酰磷脂酰胆碱（DPPC），即2-[1-13C]DPPC的13C NMR谱的温度依赖性。在Lβ'相中观察到宽度为112 ppm的轴对称谱，并且在Lα相中转变为类各向同性线（（δσ）约为7 ppm）。在中间的Pβ相中观察到这些谱的温度依赖性叠加，这表明该相表现出Lβ'相和Lα相的微观结构和动力学性质。对谱线形状的分析得出结论，Pβ'相中类各向同性线的出现主要是由于sn-2羰基处的构象变化，该变化在主要转变时完成。Pβ'相中轴向扩散速率的增加可能有助于谱线变窄。
