Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity
Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity
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DOI：
10.1074/jbc.m116.755884
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发表时间：
2017-01-13
影响因子：
4.8
通讯作者：
Xia, Di
中科院分区：
文献类型：
--
作者：
Esser, Lothar;Zhou, Fei;Xia, Di
P-糖蛋白（P-gp）是一种与癌症多药耐药相关的多特异性ATP依赖性转运蛋白;它在决定许多药物的药代动力学方面发挥着重要作用。了解P-gp的结构基础，底物多特异性受到其固有灵活性的阻碍，这是由连接P-gp两半的75个残基接头促进的。在这里，我们构建了一个突变的小鼠P-gp与缩短接头，以促进结构的确定。尽管罗丹明123和钙黄绿素-AM运输显着减少，接头缩短的突变体P-gp具有基础ATP酶活性，并结合ATP仅在其N-末端核苷酸结合域。9个独立确定的野生型，连接突变体，和甲基化的P-gp在高达3.3埃分辨率的结构显示出显着的移动的个别跨膜结构域螺旋，这与P-gp的两个半的开放和关闭运动。开闭运动改变了药物结合口袋内P-gp的表面拓扑结构，为P-gp在底物相互作用中的多特异性提供了机制解释。
P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancer; it plays important roles in determining the pharmacokinetics of many drugs. Understanding the structural basis of P-gp, substrate polyspecificity has been hampered by its intrinsic flexibility, which is facilitated by a 75-residue linker that connects the two halves of P-gp. Here we constructed a mutant murine P-gp with a shortened linker to facilitate structural determination. Despite dramatic reduction in rhodamine 123 and calcein-AM transport, the linker-shortened mutant P-gp possesses basal ATPase activity and binds ATP only in its N-terminal nucleotide-binding domain. Nine independently determined structures of wild type, the linker mutant, and a methylated P-gp at up to 3.3 angstrom resolution display significant movements of individual transmembrane domain helices, which correlated with the opening and closing motion of the two halves of P-gp. The open-and-close motion alters the surface topology of P-gp within the drug-binding pocket, providing a mechanistic explanation for the polyspecificity of P-gp in substrate interactions.