Structural analysis of nanoscale self-assembled discoidal lipid bilayers by solid-state NMR spectroscopy
Structural analysis of nanoscale self-assembled discoidal lipid bilayers by solid-state NMR spectroscopy
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DOI：
10.1529/biophysj.106.087072
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发表时间：
2006-11-01
影响因子：
3.4
通讯作者：
Rienstra, Chad M.
中科院分区：
文献类型：
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作者：
Li, Ying;Kijac, Aleksandra Z.;Rienstra, Chad M.
纳米盘是类似于新生高密度脂蛋白的盘状纳米级自组装脂质/蛋白质颗粒的示例，其降低冠状动脉疾病的风险。高密度脂蛋白的主要蛋白质组分是人载脂蛋白A-I，纳米盘的相应蛋白质组分是膜支架蛋白1（MSP 1），人载脂蛋白A-I的200个残基的脂质结合结构域。在这里，我们提出了魔角旋转（MAS）固态NMR研究均匀的C-13，N-15标记的MSP 1聚乙二醇沉淀的纳米盘。二维MAS C-13-C-13相关光谱显示出沉淀纳米盘中MSP 1的优异微观有序性。二级各向同性的化学位移在整个蛋白质是一致的，主要是螺旋结构。此外，脯氨酸的C-13化学位移衍生的骨架构象与分子带模型一致，但不与脂质结合MSP 1的栅栏模型一致。总体比较实验光谱和C-13化学位移预测从几个结构模型也有利于带模型。因此，我们的研究支持了纳米盘结构的带模型，并证明了MAS NMR研究高分子量脂质-蛋白质复合物结构的实用性。
Nanodiscs are an example of discoidal nanoscale self-assembled lipid/protein particles similar to nascent high-density lipoproteins, which reduce the risk of coronary artery disease. The major protein component of high-density lipoproteins is human apolipoprotein A-I, and the corresponding protein component of Nanodiscs is membrane scaffold protein 1 (MSP1), a 200-residue lipid-binding domain of human apolipoprotein A-I. Here we present magic-angle spinning (MAS) solid-state NMR studies of uniformly C-13, N-15-labeled MSP1 in polyethylene glycol precipitated Nanodiscs. Two-dimensional MAS C-13-C-13 correlation spectra show excellent microscopic order of MSP1 in precipitated Nanodiscs. Secondary isotropic chemical shifts throughout the protein are consistent with a predominantly helical structure. Moreover, the backbone conformations of prolines derived from their C-13 chemical shifts are consistent with the molecular belt model but not the picket fence model of lipid-bound MSP1. Overall comparison of experimental spectra and C-13 chemical shifts predicted from several structural models also favors the belt model. Our study thus supports the belt model of Nanodisc structure and demonstrates the utility of MAS NMR to study the structure of high molecular weight lipid-protein complexes.