Cryo-EM Analysis of the Conformational Landscape of Human P-glycoprotein (ABCB1) During its Catalytic Cycle
Cryo-EM Analysis of the Conformational Landscape of Human P-glycoprotein (ABCB1) During its Catalytic Cycle
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DOI：
10.1124/mol.116.104190
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发表时间：
2016-07-01
影响因子：
3.6
通讯作者：
Subramaniam, Sriram
中科院分区：
文献类型：
--
作者：
Frank, Gabriel A.;Shukla, Suneet;Subramaniam, Sriram
多药转运蛋白P-糖蛋白（P-gp，ABCB 1）是一种ATP依赖性泵，介导结构多样的药物和外源性物质跨细胞膜外排，影响药物药代动力学并促进多药耐药的发展。在ATP水解循环过程中，人P-gp的构象变化的结构信息尚未得到直接证明，虽然机制信息已被推断与P-gp及其直系同源物进行的生化和生物物理研究，或从其他ATP结合盒转运蛋白的结构。使用单粒子冷冻电子显微镜，我们报告了一个令人惊讶的发现，即在没有转运底物和核苷酸的情况下，人P-gp可以存在于开放的[核苷酸结合域（NBD）分开;向内]和封闭的（NBD关闭;向外）构象。我们还探测构象状态的人P-gp的催化循环过程中，并证明，ATP水解后，P-gp的转换通过一个完整的封闭构象，一个完整的开放构象中的ADP的存在。
The multidrug transporter P-glycoprotein (P-gp, ABCB1) is an ATP-dependent pump that mediates the efflux of structurally diverse drugs and xenobiotics across cell membranes, affecting drug pharmacokinetics and contributing to the development of multidrug resistance. Structural information about the conformational changes in human P-gp during the ATP hydrolysis cycle has not been directly demonstrated, although mechanistic information has been inferred from biochemical and biophysical studies conducted with P-gp and its orthologs, or from structures of other ATP-binding cassette transporters. Using single-particle cryo-electron microscopy, we report the surprising discovery that, in the absence of the transport substrate and nucleotides, human P-gp can exist in both open [nucleotide binding domains (NBDs) apart; inwardfacing] and closed (NBDs close; outward-facing) conformations. We also probe conformational states of human P-gp during the catalytic cycle, and demonstrate that, following ATP hydrolysis, P-gp transitions through a complete closed conformation to a complete open conformation in the presence of ADP.