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Pan J, Chen Q, Willenbring D, Mowrey D, Kong XP, Cohen A, Divito CB, Xu Y, Tang P. Structure of the pentameric ligand-gated ion channel GLIC bound with anesthetic ketamine. Structure 2012; 20:1463-9. [PMID: 22958642 PMCID: PMC3446250 DOI: 10.1016/j.str.2012.08.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 08/10/2012] [Accepted: 08/10/2012] [Indexed: 11/21/2022]
Abstract
Pentameric ligand-gated ion channels (pLGICs) are targets of general anesthetics, but a structural understanding of anesthetic action on pLGICs remains elusive. GLIC, a prokaryotic pLGIC, can be inhibited by anesthetics, including ketamine. The ketamine concentration leading to half-maximal inhibition of GLIC (58 μM) is comparable to that on neuronal nicotinic acetylcholine receptors. A 2.99 Å resolution X-ray structure of GLIC bound with ketamine revealed ketamine binding to an intersubunit cavity that partially overlaps with the homologous antagonist-binding site in pLGICs. The functional relevance of the identified ketamine site was highlighted by profound changes in GLIC activation upon cysteine substitution of the cavity-lining residue N152. The relevance is also evidenced by changes in ketamine inhibition upon the subsequent chemical labeling of N152C. The results provide structural insight into the molecular recognition of ketamine and are valuable for understanding the actions of anesthetics and other allosteric modulators on pLGICs.
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Affiliation(s)
- Jianjun Pan
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - Qiang Chen
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - Dan Willenbring
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - David Mowrey
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
- Department of Computational and System Biology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - Xiang-Peng Kong
- Department of Biochemistry, 550 First Avenue, MSB 329, New York University School of Medicine, New York, NY 10016
| | - Aina Cohen
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Rd., MS: 99, Menlo Park, CA, 94025
| | - Christopher B. Divito
- Department of Neurobiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - Yan Xu
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
- Department of Structural Biology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
- Department of Pharmacology and Chemical Biology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
| | - Pei Tang
- Department of Anesthesiology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
- Department of Computational and System Biology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
- Department of Pharmacology and Chemical Biology, Biomedical Science Tower 3, 3501 Fifth Avenue, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260
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