EMD-9641

Single-particle
5.6 Å
EMD-9641 Deposition: 01/09/2018
Map released: 20/03/2019
Last modified: 01/04/2020
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-9641

Calcium release-activated calcium channel protein 1, P288L mutant

EMD-9641

Single-particle
5.6 Å
EMD-9641 Deposition: 01/09/2018
Map released: 20/03/2019
Last modified: 01/04/2020
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Drosophila
Sample: Calcium release-activated calcium channel protein 1

Deposition Authors: Liu X, Wu G, Yang X, Shen Y
Molecular understanding of calcium permeation through the open Orai channel.
Liu X , Wu G , Yu Y, Chen X, Ji R, Lu J , Li X , Zhang X , Yang X , Shen Y
(2019) PLoS Biol , 17 , e3000096 - e3000096
PUBMED: 31009446
DOI: doi:10.1371/journal.pbio.3000096
ISSN: 1545-7885
Abstract:
The Orai channel is characterized by voltage independence, low conductance, and high Ca2+ selectivity and plays an important role in Ca2+ influx through the plasma membrane (PM). How the channel is activated and promotes Ca2+ permeation is not well understood. Here, we report the crystal structure and cryo-electron microscopy (cryo-EM) reconstruction of a Drosophila melanogaster Orai (dOrai) mutant (P288L) channel that is constitutively active according to electrophysiology. The open state of the Orai channel showed a hexameric assembly in which 6 transmembrane 1 (TM1) helices in the center form the ion-conducting pore, and 6 TM4 helices in the periphery form extended long helices. Orai channel activation requires conformational transduction from TM4 to TM1 and eventually causes the basic section of TM1 to twist outward. The wider pore on the cytosolic side aggregates anions to increase the potential gradient across the membrane and thus facilitate Ca2+ permeation. The open-state structure of the Orai channel offers insights into channel assembly, channel activation, and Ca2+ permeation.