From in silico to in vitro: a trip to reveal flavonoid binding on the Rattus norvegicus Kir6.1 ATP-sensitive inward rectifier potassium channel

• Published in: PeerJ (San Francisco, CA) CA), 2018-05, Vol.6, p.e4680-e4680, Article e4680
• Main Authors: Trezza, Alfonso, Cicaloni, Vittoria, Porciatti, Piera, Langella, Andrea, Fusi, Fabio, Saponara, Simona, Spiga, Ottavia
• Format: Article
• Language: English
• Subjects: Angina; ATP-sensitive inward rectifier potassium channel; Binding site; Binding sites; Biochemistry; Bioinformatics; Cardiovascular diseases; Cardiovascular system; Computational Biology; Computer applications; Flavonoids; Fruits; Heart; Homology; Homology modeling; Hyperinsulinemia; Hypoglycemia; Insulin; Kinases; Life sciences; Metabolism; Molecular dynamics; Molecular modelling; Myocytes; Patch clamp; Pharmacology; Physiology; Polyamines; Potassium; Potassium channel; Potassium channels; Potassium channels (inwardly-rectifying); Proteins; Quercetin; Rattus norvegicus; Rodents; Rutin
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.4680

ATP-sensitive inward rectifier potassium channels (Kir), are a potassium channel family involved in many physiological processes. K dysfunctions are observed in several diseases such as hypoglycaemia, hyperinsulinemia, Prinzmetal angina-like symptoms, cardiovascular diseases. A broader view of the K mechanism is needed in order to operate on their regulation, and in this work we clarify the structure of the ATP-sensitive inward rectifier potassium channel 8 (Kir6.1), which has been obtained through a homology modelling procedure. Due to the medical use of flavonoids, a considerable increase in studies on their influence on human health has recently been observed, therefore our aim is to study, through computational methods, the three-dimensional (3D) conformation together with mechanism of action of Kir6.1 with three flavonoids. Computational analysis by performing molecular dynamics (MD) and docking simulation on rat 3D modelled structure have been completed, in its closed and open conformation state and in complex with Quercetin, 5-Hydroxyflavone and Rutin flavonoids. Our study showed that only Quercetin and 5-Hydroxyflavone were responsible for a significant down-regulation of the Kir6.1 activity, stabilising it in a closed conformation. This hypothesis was supported by in vitro experiments demonstrating that Quercetin and 5-Hydroxyflavone were capable to inhibit K currents of rat tail main artery myocytes recorded by the patch-clamp technique. Combined methodological approaches, such as molecular modelling, docking and MD simulations of Kir6.1 channel, used to elucidate flavonoids intrinsic mechanism of action, are introduced, revealing a new potential druggable protein site.