Dodecylphosphocholine micelles as a membrane like environment:: new results from NMR relaxation and paramagnetic relaxation enhancement analysis
Dodecylphosphocholine micelles as a membrane like environment:: new results from NMR relaxation and paramagnetic relaxation enhancement analysis
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DOI：
10.1007/s002490050182
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发表时间：
1998-01-01
影响因子：
2
通讯作者：
Neumann, JM
中科院分区：
文献类型：
--
作者：
Beswick, V;Guerois, R;Neumann, JM
为了进一步研究十二烷基磷酸胆碱（DPC）胶束模拟磷脂酰胆碱双层环境的程度，我们进行了C-13，H-2和P-31 NMR弛豫测量。我们的数据表明，DPC磷酸胆碱基团在低温（12摄氏度）的动态行为对应于在高温（51摄氏度）的磷脂酰胆碱界面。在存在螺旋肽、PMP 1片段或膜联蛋白片段的情况下，DPC局部动力学不受影响，而DPC聚集数增加以匹配用于容纳结合肽的适当面积/体积比。我们还表明，定量测量的顺磁弛豫增强诱导少量的自旋标记的磷脂肽质子信号提供了一个有意义的见解的位置上的PMP 1和膜联蛋白片段在DPC胶束。从两种肽的NOESY光谱的残基内交叉峰提取对弛豫的顺磁贡献。发现胶束中每个肽的位置与相应的弛豫数据一致。如PMP 1片段的研究所示，顺磁弛豫数据也使我们能够提供缺失的中程NOE，从而完成胶束中肽的标准构象分析。
To further examine to what extent a dodecylphosphocholine (DPC) micelle mimics a phospbatidylcholine bilayer environment, we performed C-13, H-2, and P-31 NMR relaxation measurements. Our data show that the dynamic behavior of DPC phosphocholine groups at low temperature (12 degrees C) corresponds to that of a phosphatidylcholine interface at high temperature (51 degrees C). In the presence of helical peptides, a PMP1 fragment, or an annexin fragment, the DPC local dynamics are not affected whereas the DPC aggregation number is increased to match an appropriate area/volume ratio for accommodating the bound peptides. We also show that quantitative measurements of paramagnetic relaxation enhancements induced by small amounts of spin-labeled phospholipids on peptide proton signals provide a meaningful insight on the location of both PMP1 and annexin fragments in DPC micelles. The paramagnetic contributions to the relaxation were extracted from intra-residue cross-peaks of NOESY spectra for both peptides. The location of each peptide in the micelles was found consistent with the corresponding relaxation data. As illustrated by the study of the PMP1 fragment, paramagnetic relaxation data also allow us to supply the missing medium-range NOEs and therefore to complete a standard conformational analysis of peptides in micelles.