title: Three pairs of weak interactions precisely regulate the G-loop gate of Kir2.1 channel.
abstract: Kir2.1 (also known as IRK1) plays key roles in regulation of resting membrane potential and cell excitability. To achieve its physiological roles, Kir2.1 performs a series of conformational transition, named as gating. However, the structural basis of gating is still obscure. Here, we combined site-directed mutation, two-electrode voltage clamp with molecular dynamics simulations and determined that H221 regulates the gating process of Kir2.1 by involving a weak interaction network. Our data show that the H221R mutant accelerates the rundown kinetics and decelerates the reactivation kinetics of Kir2.1. Compared with the WT channel, the H221R mutation strengthens the interaction between the CD- and G-loops (E303-R221) which stabilizes the close state of the G-loop gate and weakens the interactions between C-linker and CD-loop (R221-R189) and the adjacent G-loops (E303-R312) which destabilizes the open state of G-loop gate. Our data indicate that the three pairs of interactions (E303-H221, H221-R189 and E303-R312) precisely regulate the G-loop gate by controlling the conformation of G-loop. Proteins 2016; 84:1929-1937. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, 300401, China.|Department of Electrical Engineering and Computer Science, Hebei University of Technology, Langfang, 065000, China.
authors.forename: Junwei
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Urban Planning, School of Architecture and Art Design, Hebei University of Technology, Tianjin, 300401, China.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, 300401, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Mathematics and Physics, North China Electric Power University, Baoding, 071003, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, 300401, China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Pang
authors.affiliation: Department of Mechatronics Engineering, Hebei University of Technology, Tianjin, 300130, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Neural and Vascular Biology, Ministry of Education, The Key Laboratory of Pharmacology and Toxicology for New Drug, Hebei Province, Department of Pharmacology, Hebei Medical University, Shijiazhuang, 050017, China.
authors.forename: Hailin
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, 23298.
authors.forename: Diomedes E
authors.initials: DE
authors.lastname: Logothetis
authors.affiliation: Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, 300401, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhan
authors.affiliation: Key Laboratory of Molecular Biophysics, Hebei Province, Institute of Biophysics, School of Sciences, Hebei University of Technology, Tianjin, 300401, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: An
mesh_terms: D000818:Animals; D002645:Chickens; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D015640:Ion Channel Gating; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship; D014982:Xenopus laevis
chemical_list: D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; C497069:Kcnj6 protein, mouse; C489461:Kir2.1 channel; C489463:Kir2.2 channel; D024661:Potassium Channels, Inwardly Rectifying; D011994:Recombinant Proteins
keywords: Kir channel; gating kinetics; homology model; molecular dynamics; targeted molecular dynamics; weak interaction