title: Solid phase synthesis, NMR structure determination of α-KTx3.8, its in silico docking to Kv1.x potassium channels, and electrophysiological analysis provide insights into toxin-channel selectivity.
abstract: Animal venoms, such as those from scorpions, are a potent source for new pharmacological substances. In this study we have determined the structure of the α-KTx3.8 (named as Bs6) scorpion toxin by multidimensional (1)H homonuclear NMR spectroscopy and investigated its function by molecular dynamics (MD) simulations and electrophysiological measurements. Bs6 is a potent inhibitor of the Kv1.3 channel which plays an important role during the activation and proliferation of memory T-cells (TEM), which play an important role in autoimmune diseases. Therefore, it could be an interesting target for treatment of autoimmune diseases. In this study, Bs6 was synthesised by solid phase synthesis and its three-dimensional (3D) structure has been determined. To gain a deeper insight into the interaction of Bs6 with different potassium channels like hKv1.1 and hKv1.3, the protein-protein complex was modelled based on known toxin-channel structures and tested for stability in MD simulations using GROMACS. The toxin-channel interaction was further analysed by electrophysiological measurements of different potassium channels like hKv1.3 and hKv7.1. As potassium channel inhibitors could play an important role to overcome autoimmune diseases like multiple sclerosis and type-1 diabetes mellitus, our data contributes to the understanding of the molecular mechanism of action and will ultimately help to develop new potent inhibitors in future.
authors.affiliation: Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Biomolecular Spectroscopy, Ruhr University of Bochum, D-44780 Bochum, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Kohl
authors.affiliation: Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Rothenberg
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany; HEJ Research Institute of Chemistry, ICCBS, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Syed Abid
authors.initials: SA
authors.lastname: Ali
authors.affiliation: Dow International College, Dow University of Health Sciences, Karachi 75270, Pakistan.
authors.forename: Mehtab
authors.initials: M
authors.lastname: Alam
authors.affiliation: Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D-48149 Münster, Germany.
authors.forename: Guiscard
authors.initials: G
authors.lastname: Seebohm
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Kalbacher
authors.affiliation: Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen D-72076, Germany. Electronic address: Wolfgang.Voelter@uni-tuebingen.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Voelter
authors.affiliation: Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Biomolecular Spectroscopy, Ruhr University of Bochum, D-44780 Bochum, Germany. Electronic address: Raphael.Stoll@ruhr-uni-bochum.de.
authors.forename: Raphael
authors.initials: R
authors.lastname: Stoll
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000188:drug therapy; D049109:Cell Proliferation / Q000187:drug effects; D018999:Charybdotoxin / Q000378:metabolism; D055724:Electrophysiological Phenomena; D006801:Humans; D020128:Inhibitory Concentration 50; D051657:KCNQ1 Potassium Channel / Q000737:chemistry; D051664:Kv1.3 Potassium Channel / Q000037:antagonists & inhibitors / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008968:Molecular Conformation; D062105:Molecular Docking Simulation; D026902:Potassium Channel Blockers / Q000737:chemistry / Q000494:pharmacology; D011487:Protein Conformation; D012604:Scorpion Venoms / Q000737:chemistry* / Q000494:pharmacology; D012605:Scorpions / Q000378:metabolism; D051637:Shaker Superfamily of Potassium Channels / Q000737:chemistry*; D060327:Solid-Phase Synthesis Techniques / Q000379:methods*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism
chemical_list: D051657:KCNQ1 Potassium Channel; D051664:Kv1.3 Potassium Channel; D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; D051637:Shaker Superfamily of Potassium Channels; D018999:Charybdotoxin
keywords: Docking; NMR; Potassium channel inhibitor; Scorpion toxin; Solid phase synthesis; TEVC method