Fluorine-19 NMR and computational quantification of isoflurane binding to the voltage-gated sodium channel NaChBac.

Autor: Kinde MN; Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261., Bondarenko V; Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261., Granata D; Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA 19122., Bu W; Department of Anesthesiology & Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104., Grasty KC; Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102., Loll PJ; Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102., Carnevale V; Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA 19122., Klein ML; Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA 19122; mlklein@temple.edu xuy@anes.upmc.edu., Eckenhoff RG; Department of Anesthesiology & Critical Care, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104., Tang P; Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.; Department of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261., Xu Y; Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; mlklein@temple.edu xuy@anes.upmc.edu.; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2016 Nov 29; Vol. 113 (48), pp. 13762-13767. Date of Electronic Publication: 2016 Nov 15.
DOI: 10.1073/pnas.1609939113
Abstrakt: Voltage-gated sodium channels (Na V ) play an important role in general anesthesia. Electrophysiology measurements suggest that volatile anesthetics such as isoflurane inhibit Na V by stabilizing the inactivated state or altering the inactivation kinetics. Recent computational studies suggested the existence of multiple isoflurane binding sites in Na V , but experimental binding data are lacking. Here we use site-directed placement of 19 F probes in NMR experiments to quantify isoflurane binding to the bacterial voltage-gated sodium channel NaChBac. 19 F probes were introduced individually to S129 and L150 near the S4-S5 linker, L179 and S208 at the extracellular surface, T189 in the ion selectivity filter, and all phenylalanine residues. Quantitative analyses of 19 F NMR saturation transfer difference (STD) spectroscopy showed a strong interaction of isoflurane with S129, T189, and S208; relatively weakly with L150; and almost undetectable with L179 and phenylalanine residues. An orientation preference was observed for isoflurane bound to T189 and S208, but not to S129 and L150. We conclude that isoflurane inhibits NaChBac by two distinct mechanisms: (i) as a channel blocker at the base of the selectivity filter, and (ii) as a modulator to restrict the pivot motion at the S4-S5 linker and at a critical hinge that controls the gating and inactivation motion of S6.
Competing Interests: The authors declare no conflict of interest.
Databáze: MEDLINE
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