气候变化领域集成服务门户(CCPortal): Sodium and proton coupling in the conformational cycle of a MATE antiporter from Vibrio cholerae

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DOI	10.1073/pnas.1802417115
	Sodium and proton coupling in the conformational cycle of a MATE antiporter from Vibrio cholerae
	Claxton D.P.; Jagessar K.L.; Ryan Steed P.; Stein R.A.; Mchaourab H.S.
发表日期	2018
ISSN	0027-8424
起始页码	E6182
结束页码	E6190
卷号	115 期号:27
英文摘要	Secondary active transporters belonging to the multidrug and toxic compound extrusion (MATE) family harness the potential energy of electrochemical ion gradients to export a broad spectrum of cytotoxic compounds, thus contributing to multidrug resistance. The current mechanistic understanding of ion-coupled substrate transport has been informed by a limited set of MATE transporter crystal structures from multiple organisms that capture a 12-transmembrane helix topology adopting similar outward-facing conformations. Although these structures mapped conserved residues important for function, the mechanistic role of these residues in shaping the conformational cycle has not been investigated. Here, we use double-electron electron resonance (DEER) spectroscopy to explore ligand-dependent conformational changes of NorM from Vibrio cholerae (NorM-Vc), a MATE transporter proposed to be coupled to both Na+ and H+ gradients. Distance measurements between spin labels on the periplasmic side of NorM-Vc identified unique structural intermediates induced by binding of Na+, H+, or the substrate doxorubicin. The Na+- and H+-dependent intermediates were associated with distinct conformations of TM1. Site-directed mutagenesis of conserved residues revealed that Na+- and H+-driven conformational changes are facilitated by a network of polar residues in the N-terminal domain cavity, whereas conserved carboxylates buried in the C-terminal domain are critical for stabilizing the drug-bound state. Interpreted in conjunction with doxorubicin binding of mutant NorM-Vc and cell toxicity assays, these results establish the role of ion-coupled conformational dynamics in the functional cycle and implicate H+ in the doxorubicin release mechanism. © 2018 National Academy of Sciences. All Rights Reserved.
英文关键词	DEER; EPR; MATE; NorM; Transport mechanism
语种	英语
scopus关键词	carboxylic acid; carrier protein; doxorubicin; MATE protein; proton; sodium ion; TM1 protein; unclassified drug; antiporter; bacterial protein; NorM protein, bacteria; proton; sodium; amino acid sequence; amino terminal sequence; Article; carboxy terminal sequence; conformational transition; controlled study; crystal structure; cytotoxicity; double electron electron resonance spectroscopy; nonhuman; periplasm; priority journal; protein binding; protein conformation; protein domain; site directed mutagenesis; spectroscopy; Vibrio cholerae; chemistry; genetics; metabolism; Vibrio cholerae; Antiporters; Bacterial Proteins; Doxorubicin; Protein Domains; Protons; Sodium; Vibrio cholerae
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160500
作者单位	Claxton, D.P., Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States; Jagessar, K.L., Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States; Ryan Steed, P., Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States; Stein, R.A., Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States; Mchaourab, H.S., Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, United States
推荐引用方式 GB/T 7714	Claxton D.P.,Jagessar K.L.,Ryan Steed P.,et al. Sodium and proton coupling in the conformational cycle of a MATE antiporter from Vibrio cholerae[J],2018,115(27).
APA	Claxton D.P.,Jagessar K.L.,Ryan Steed P.,Stein R.A.,&Mchaourab H.S..(2018).Sodium and proton coupling in the conformational cycle of a MATE antiporter from Vibrio cholerae.Proceedings of the National Academy of Sciences of the United States of America,115(27).
MLA	Claxton D.P.,et al."Sodium and proton coupling in the conformational cycle of a MATE antiporter from Vibrio cholerae".Proceedings of the National Academy of Sciences of the United States of America 115.27(2018).