7tbg | pdb_00007tbg
AtTPC1 D454N with 1 mM Ca2+
Structural highlights
Function[TPC1_ARATH] Functions as a voltage-gated inward-rectifying Ca(2+) channel (VDCC) across the vacuole membrane. Is one of the essential components of the slow vacuolar (SV) channel. Acts as the major ROS-responsive Ca(2+) channel and is the possible target of Al-dependent inhibition. Involved in the regulation of germination and stomatal movement.[1] [2] Publication Abstract from PubMedVoltage-gated ion channels confer excitability to biological membranes, initiating and propagating electrical signals across large distances on short timescales. Membrane excitation requires channels that respond to changes in electric field and couple the transmembrane voltage to gating of a central pore. To address the mechanism of this process in a voltage-gated ion channel, we determined structures of the plant two-pore channel 1 at different stages along its activation coordinate. These high-resolution structures of activation intermediates, when compared with the resting-state structure, portray a mechanism in which the voltage-sensing domain undergoes dilation and in-membrane plane rotation about the gating charge-bearing helix, followed by charge translocation across the charge transfer seal. These structures, in concert with patch-clamp electrophysiology, show that residues in the pore mouth sense inhibitory Ca(2+) and are allosterically coupled to the voltage sensor. These conformational changes provide insight into the mechanism of voltage-sensor domain activation in which activation occurs vectorially over a series of elementary steps. Molecular basis of multistep voltage activation in plant two-pore channel 1.,Dickinson MS, Lu J, Gupta M, Marten I, Hedrich R, Stroud RM Proc Natl Acad Sci U S A. 2022 Mar 1;119(9). pii: 2110936119. doi:, 10.1073/pnas.2110936119. PMID:35210362[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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