title: Fluorescent system based on bacterial expression of hybrid KcsA channels designed for Kv1.3 ligand screening and study.
abstract: Human voltage-gated potassium channel Kv1.3 is an important pharmacological target for the treatment of autoimmune and metabolic diseases. Increasing clinical demands stipulate an active search for efficient and selective Kv1.3 blockers. Here we present a new, reliable, and easy-to-use analytical system designed to seek for and study Kv1.3 ligands that bind to the extracellular vestibule of the K(+)-conducting pore. It is based on Escherichia coli spheroplasts with the hybrid protein KcsA-Kv1.3 embedded into the membrane, fluorescently labeled Kv1.3 blocker agitoxin-2, and confocal laser scanning microscopy as a detection method. This system is a powerful alternative to radioligand and patch-clamp techniques. It enables one to search for Kv1.3 ligands both among individual compounds and in complex mixtures, as well as to characterize their affinity to Kv1.3 channel using the "mix and read" mode. To demonstrate the potential of the system, we performed characterization of several known Kv1.3 ligands, tested nine spider venoms for the presence of Kv1.3 ligands, and conducted guided purification of a channel blocker from scorpion venom.
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia.
authors.forename: Kseniya S
authors.initials: KS
authors.lastname: Kudryashova
authors.forename: Oksana V
authors.initials: OV
authors.lastname: Nekrasova
authors.forename: Alexey I
authors.initials: AI
authors.lastname: Kuzmenkov
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Vassilevski
authors.forename: Anastasia A
authors.initials: AA
authors.lastname: Ignatova
authors.forename: Yuliya V
authors.initials: YV
authors.lastname: Korolkova
authors.forename: Eugene V
authors.initials: EV
authors.lastname: Grishin
authors.forename: Mikhail P
authors.initials: MP
authors.lastname: Kirpichnikov
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Feofanov
mesh_terms: D000818:Animals; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D051664:Kv1.3 Potassium Channel / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D018613:Microscopy, Confocal / Q000379:methods*; D024642:Potassium Channels, Voltage-Gated / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012604:Scorpion Venoms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012605:Scorpions; D013104:Spheroplasts / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013111:Spider Venoms / Q000737:chemistry; D013112:Spiders
chemical_list: D051664:Kv1.3 Potassium Channel; D008024:Ligands; D024642:Potassium Channels, Voltage-Gated; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D013111:Spider Venoms; C087603:agitoxin 2