Positioning membrane proteins by novel protein engineering and biophysical approaches.
Positioning membrane proteins by novel protein engineering and biophysical approaches.
复制标题
通过新颖的蛋白质工程和生物物理方法定位膜蛋白。
DOI：
10.1016/j.jmb.2005.06.080
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发表时间：
2005
影响因子：
5.6
通讯作者：
He,Xiaomei
中科院分区：
文献类型：
--
作者：
Tatulian,SurenA;Qin,Shan;Pande,AbhayH;He,Xiaomei
膜蛋白是独特的，因为它们只有在以独特的方式结合到细胞膜时才能正常发挥功能。因此，除了三维结构之外，还需要膜蛋白相对于膜的定位，以了解其详细的分子机制。迄今为止已经确定的膜蛋白的原子分辨率结构提供了与膜无关的任意坐标系中的原子坐标，因此提供了很少或没有关于蛋白质如何与膜相互作用的信息。这对于外周膜蛋白尤其如此，因为它们与整合蛋白不同，缺乏明确的疏水跨膜结构域。在这里，我们提出了一种新的技术，用于确定的蛋白质膜复合物，涉及蛋白质连接，节段性同位素标记，偏振红外光谱，膜深度依赖性荧光猝灭，和解析几何算法的配置。我们已经应用这种方法来确定膜结合磷脂酶A2的结构。我们的研究结果提供了一个前所未有的膜结合蛋白质的结构，其中每个原子的z坐标是从膜中心的距离，因此允许每个氨基酸相对于膜的精确位置。鉴于膜结合蛋白相对于膜的方向和位置的功能意义，我们建议将这种结构特征指定为膜蛋白的“五元”结构。
Membrane proteins are unique, in that they can function properly only when they are bound to cellular membranes in a distinct manner. Therefore, positioning of membrane proteins with respect to the membrane is required in addition to the three-dimensional structures in order to understand their detailed molecular mechanisms. Atomic-resolution structures of membrane proteins that have been determined to date provide the atom coordinates in arbitrary coordinate systems with no relation to the membrane and therefore provide little or no information on how the protein would interact with the membrane. This is especially true for peripheral membrane proteins, because they, unlike integral proteins, are devoid of well-defined hydrophobic transmembrane domains. Here, we present a novel technique for determination of the configuration of a protein–membrane complex that involves protein ligation, segmental isotope labeling, polarized infrared spectroscopy, membrane depth-dependent fluorescence quenching, and analytical geometry algorithms. We have applied this approach to determine the structure of a membrane-bound phospholipase A2. Our results provide an unprecedented structure of a membrane-bound protein in which the z-coordinate of each atom is the distance from the membrane center and therefore allows precise location of each amino acid relative to the membrane. Given the functional significance of the orientation and location of membrane-bound proteins with respect to the membrane, we propose to specify this structural feature as the “quinary” structure of membrane proteins.