6tir
From Proteopedia
NOE based model of hVDAC-1 bound to beta-NADH in detergent micelles
Structural highlights
Function[VDAC1_HUMAN] Forms a channel through the mitochondrial outer membrane and also the plasma membrane. The channel at the outer mitochondrial membrane allows diffusion of small hydrophilic molecules; in the plasma membrane it is involved in cell volume regulation and apoptosis. It adopts an open conformation at low or zero membrane potential and a closed conformation at potentials above 30-40 mV. The open state has a weak anion selectivity whereas the closed state is cation-selective. May participate in the formation of the permeability transition pore complex (PTPC) responsible for the release of mitochondrial products that triggers apoptosis.[1] [2] [3] Publication Abstract from PubMedThe voltage-dependent anion channel (VDAC) forms the primary diffusion pore of the outer mitochondrial membrane. In its apo form, VDAC adopts an open conformation with high conductance. States of lower conductance can be induced by ligand binding or the application of voltage. Here, we clarify at the atomic level how beta-NADH binding leads to a low-conductance state and characterize the role of the VDAC N-terminal helix in voltage gating. A high-resolution NMR structure of human VDAC-1 with bound NADH, combined with molecular dynamics simulation show that beta-NADH binding reduces the pore conductance sterically without triggering a structural change. Electrophysiology recordings of crosslinked protein variants and NMR relaxation experiments probing different time scales show that increased helix dynamics is present in the open state and that motions of the N-terminal helices are involved in the VDAC voltage gating mechanism. The Structural Basis for Low Conductance in the Membrane Protein VDAC upon beta-NADH Binding and Voltage Gating.,Bohm R, Amodeo GF, Murlidaran S, Chavali S, Wagner G, Winterhalter M, Brannigan G, Hiller S Structure. 2019 Dec 10. pii: S0969-2126(19)30433-2. doi:, 10.1016/j.str.2019.11.015. PMID:31862297[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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