A Usual G-Protein-Coupled Receptor in Unusual Membranes.
A Usual G-Protein-Coupled Receptor in Unusual Membranes.
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DOI：
10.1002/anie.201508648
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发表时间：
2016-01-11
期刊：
影响因子：
--
通讯作者：
Liang H
中科院分区：
文献类型：
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作者：
Chawla U;Jiang Y;Zheng W;Kuang L;Perera SM;Pitman MC;Brown MF;Liang H
G蛋白偶联受体（GPCR）是最大的膜结合受体家族，占所有已知药物靶点的约50%。它们为膜蛋白纳米技术提供了巨大的潜力。我们在这里报告的电荷相互作用定向重建机制，诱导自发插入牛视紫红质，真核GPCR，到脂质和聚合物为基础的人工膜。我们揭示了一种新的别构模式的视紫红质激活引起的非生物膜：阳离子膜驱动的过渡，从非活性MI激活MII状态的情况下，高[H+]或负的自发曲率。我们将这种激活归因于膜表面和去质子化的Glu 134残基的视紫红质保守的ERY序列基序，有助于打破细胞质的“离子锁”之间的吸引力电荷相互作用。这项研究揭示了一种新的非生物膜的设计概念，以重建和利用合成系统中的GPCR功能。暗态（1U 19;蓝色）的膜包埋视紫红质（左）与其活化的MII态（3 PXO;黄色）重叠。暗态下的细胞质“离子锁”（即Glu 134-Arg 135盐桥）（右上）被阳离子膜表面部分和去质子化Glu 134（右下）之间的吸引电荷相互作用打破，这是一种自由能下降过程，有助于光活化后视紫红质构象变化。
G-protein-coupled receptors (GPCRs) are the largest family of membrane-bound receptors and constitute ~50% of all known drug targets. They offer great potential for membrane protein nanotechnologies. We report here a charge-interaction-directed reconstitution mechanism that induces spontaneous insertion of bovine rhodopsin, the eukaryotic GPCR, into both lipid- and polymer-based artificial membranes. We reveal a new allosteric mode of rhodopsin activation incurred by the non-biological membranes: the cationic membrane drives a transition from inactive MI to activated MII state in the absence of high [H+] or negative spontaneous curvature. We attribute this activation to the attractive charge interaction between the membrane surface and the deprotonated Glu134 residue of the rhodopsin-conserved ERY sequence motif that helps break the cytoplasmic “ionic lock”. This study unveils a novel design concept of non-biological membranes to reconstitute and harness GPCR functions in synthetic systems. Membrane-embedded rhodopsin (left) in dark state (1U19; blue) overlaid with its activated MII state (3PXO; yellow). The cytoplasmic “ionic lock” (i.e. Glu134-Arg135 salt bridge) in the dark state (top right) is broken by attractive charge interactions between the cationic membrane surface moieties and deprotonated Glu134 (bottom right), a free energy downhill process that facilitates the rhodopsin conformation change upon photoactivation.