Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, ion channel, molecular dynamics, neurotoxin, nuclear magnetic resonance (NMR), peptides, potassium channel, protein motif, protein structure, alpha-hairpinin, hefutoxin, pore blocker, HELICAL HAIRPIN STRUCTURE, ION CHANNELS, COUPLING-CONSTANTS, K+ CHANNEL, PEPTIDE, ORGANIZATION, INHIBITOR, RESIDUES, TARGETS, TOXINS, Amino Acid Sequence, Animals, Humans, Kv1.3 Potassium Channel, Ligands, Magnetic Resonance Spectroscopy, Mass Spectrometry, Molecular Dynamics Simulation, Mutation, Peptides, Potassium Channel Blockers, Protein Binding, Protein Conformation, Proteins, Surface Properties, 03 Chemical Sciences, 06 Biological Sciences, 11 Medical and Health Sciences, 31 Biological sciences, 32 Biomedical and clinical sciences, 34 Chemical sciences

Abstract:

Tk-hefu is an artificial peptide designed based on the α-hairpinin scaffold, which selectively blocks voltage-gated potassium channels Kv1.3. Here we present its spatial structure resolved by NMR spectroscopy and analyze its interaction with channels using computer modeling. We apply protein surface topography to suggest mutations and increase Tk-hefu affinity to the Kv1.3 channel isoform. We redesign the functional surface of Tk-hefu to better match the respective surface of the channel pore vestibule. The resulting peptide Tk-hefu-2 retains Kv1.3 selectivity and displays ∼15 times greater activity compared with Tk-hefu. We verify the mode of Tk-hefu-2 binding to the channel outer vestibule experimentally by site-directed mutagenesis. We argue that scaffold engineering aided by protein surface topography represents a reliable tool for design and optimization of specific ion channel ligands.