title: Complexes of Peptide Blockers with Kv1.6 Pore Domain: Molecular Modeling and Studies with KcsA-Kv1.6 Channel.
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.
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.|Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: O V
authors.initials: OV
authors.lastname: Nekrasova
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.
authors.forename: A D
authors.initials: AD
authors.lastname: Volyntseva
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.|Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: K S
authors.initials: KS
authors.lastname: Kudryashova
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.
authors.forename: V N
authors.initials: VN
authors.lastname: Novoseletsky
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.
authors.forename: E A
authors.initials: EA
authors.lastname: Lyapina
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Illarionova
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: S A
authors.initials: SA
authors.lastname: Yakimov
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: Yu V
authors.initials: YV
authors.lastname: Korolkova
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.
authors.forename: K V
authors.initials: KV
authors.lastname: Shaitan
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia.|Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
authors.forename: M P
authors.initials: MP
authors.lastname: Kirpichnikov
authors.affiliation: Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, 119992, Russia. avfeofanov@yandex.ru.|Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997, Moscow, Russia. avfeofanov@yandex.ru.
authors.forename: A V
authors.initials: AV
authors.lastname: Feofanov
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051667:Kv1.6 Potassium Channel; D008958:Models, Molecular; D026902:Potassium Channel Blockers / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051637:Shaker Superfamily of Potassium Channels / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C064389:KCNA6 protein, human; D051667:Kv1.6 Potassium Channel; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D051637:Shaker Superfamily of Potassium Channels; C107790:prokaryotic potassium channel
keywords: Binding assay; Membrane protein expression; Molecular dynamics; Molecular modeling; Scorpion toxins; Voltage-gated potassium channel