6m84

Crystal structure of cKir2.2 force open mutant in complex with PI(4,5)P2

spinqualitylabelsall models 6m84, resolution 2.81Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6m84 is a 1 chain structure with sequence from Gallus gallus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.81Å Ligands: K, LMT, PIO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function KCJ12_CHICK Inward rectifying potassium channel that is activated by phosphatidylinositol 4,5-bisphosphate and that probably participates in controlling the resting membrane potential in electrically excitable cells. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. The inward rectification is probably due to the blockage of outward current by cytoplasmic polyamines and/or magnesium ions. Publication Abstract from PubMed Potassium ion conduction through open potassium channels is essential to control of membrane potentials in all cells. To elucidate the open conformation and hence the mechanism of K+ ion conduction in the classic inward rectifier Kir2.2, we introduced a negative charge (G178D) at the crossing point of the inner helix bundle, the location of ligand-dependent gating. This "forced open" mutation generated channels that were active even in the complete absence of phosphatidylinositol-4,5-bisphosphate (PIP2), an otherwise essential ligand for Kir channel opening. Crystal structures were obtained at a resolution of 3.6 A without PIP2 bound, or 2.8 A in complex with PIP2. The latter revealed a slight widening at the helix bundle crossing (HBC) through backbone movement. MD simulations showed that subsequent spontaneous wetting of the pore through the HBC gate region allowed K+ ion movement across the HBC and conduction through the channel. Further simulations reveal atomistic details of the opening process and highlight the role of pore-lining acidic residues in K+ conduction through Kir2 channels. Atomistic basis of opening and conduction in mammalian inward rectifier potassium (Kir2.2) channels.,Zangerl-Plessl EM, Lee SJ, Maksaev G, Bernsteiner H, Ren F, Yuan P, Stary-Weinzinger A, Nichols CG J Gen Physiol. 2020 Jan 6;152(1). pii: jgp.201912422. doi: 10.1085/jgp.201912422. PMID:31744859 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Potassium channel 3D structures

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