1. Complexes of Peptide Blockers with Kv1.6 Pore Domain: Molecular Modeling and Studies with KcsA-Kv1.6 Channel.
- Author
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Nekrasova OV, Volyntseva AD, Kudryashova KS, Novoseletsky VN, Lyapina EA, Illarionova AV, Yakimov SA, Korolkova YV, Shaitan KV, Kirpichnikov MP, and Feofanov AV
- Subjects
- Amino Acid Sequence, Bacterial Proteins chemistry, Bacterial Proteins genetics, Dose-Response Relationship, Drug, Humans, Kv1.6 Potassium Channel, Potassium Channel Blockers chemistry, Potassium Channel Blockers pharmacology, Potassium Channels chemistry, Potassium Channels genetics, Protein Binding physiology, Protein Structure, Secondary, Protein Structure, Tertiary, Shaker Superfamily of Potassium Channels chemistry, Shaker Superfamily of Potassium Channels genetics, Bacterial Proteins antagonists & inhibitors, Bacterial Proteins metabolism, Models, Molecular, Potassium Channel Blockers metabolism, Potassium Channels metabolism, Shaker Superfamily of Potassium Channels antagonists & inhibitors, Shaker Superfamily of Potassium Channels metabolism
- Abstract
Potassium voltage-gated Kv1.6 channel, which is distributed primarily in neurons of central and peripheral nervous systems, is of significant physiological importance. To date, several high-affinity Kv1.6-channel blockers are known, but the lack of selective ones among them hampers the studies of tissue localization and functioning of Kv1.6 channels. Here we present an approach to advanced understanding of interactions of peptide toxin blockers with a Kv1.6 pore. It combines molecular modeling studies and an application of a new bioengineering system based on a KcsA-Kv1.6 hybrid channel for the quantitative fluorescent analysis of blocker-channel interactions. Using this system we demonstrate that peptide toxins agitoxin 2, kaliotoxin1 and OSK1 have similar high affinity to the extracellular vestibule of the K
+ -conducting pore of Kv1.6, hetlaxin is a low-affinity ligand, whereas margatoxin and scyllatoxin do not bind to Kv1.6 pore. Binding of toxins to Kv1.6 pore has considerable inverse dependence on the ionic strength. Model structures of KcsA-Kv1.6 and Kv1.6 complexes with agitoxin 2, kaliotoxin 1 and OSK1 were obtained using homology modeling and molecular dynamics simulation. Interaction interfaces, which are formed by 15-19 toxin residues and 10 channel residues, are described and compared. Specific sites of Kv1.6 pore recognition are identified for targeting of peptide blockers. Analysis of interactions between agitoxin 2 derivatives with point mutations (S7K, S11G, L19S, R31G) and KcsA-Kv1.6 confirms reliability of the calculated complex structure.- Published
- 2017
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