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Journal Article

Voltage dependence of conformational dynamics and subconducting states of VDAC-1.

MPS-Authors
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Briones,  R.
Research Group of Computational Biomolecular Dynamics, MPI for biophysical chemistry, Max Planck Society;

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Giller,  K.
Department of NMR Based Structural Biology, MPI for biophysical chemistry, Max Planck Society;

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Zweckstetter,  M.
Research Group of Protein Structure Determination using NMR, MPI for biophysical chemistry, Max Planck Society;

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Griesinger,  C.
Department of NMR Based Structural Biology, MPI for biophysical chemistry, Max Planck Society;

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Becker,  S.
Department of NMR Based Structural Biology, MPI for biophysical chemistry, Max Planck Society;

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de Groot,  B. L.
Research Group of Computational Biomolecular Dynamics, MPI for biophysical chemistry, Max Planck Society;

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Fulltext (public)

2350775.pdf
(Publisher version), 2MB

Supplementary Material (public)

2350775_Suppl_1.pdf
(Supplementary material), 7MB

2350775_Suppl_2.pdf
(Supplementary material), 8MB

Citation

Briones, R., Weichbrodt, C., Paltrinieri, L., Mey, I., Villinger, S., Giller, K., et al. (2016). Voltage dependence of conformational dynamics and subconducting states of VDAC-1. Biophysical Journal, 111(6), 1223-1234. doi:10.1016/j.bpj.2016.08.007.


Cite as: http://hdl.handle.net/11858/00-001M-0000-002B-81A5-C
Abstract
The voltage-dependent anion channel 1 (VDAC-1) is an important protein of the outer mitochondrial membrane that transports energy metabolites and is involved in apoptosis. The available structures of VDAC proteins show a wide β-stranded barrel pore, with its N-terminal α-helix (N-α) bound to its interior. Electrophysiology experiments revealed that voltage, its polarity, and membrane composition modulate VDAC currents. Experiments with VDAC-1 mutants identified amino acids that regulate the gating process. However, the mechanisms for how these factors regulate VDAC-1, and which changes they trigger in the channel, are still unknown. In this study, molecular dynamics simulations and single-channel experiments of VDAC-1 show agreement for the current-voltage relationships of an "open" channel and they also show several subconducting transient states that are more cation selective in the simulations. We observed voltage-dependent asymmetric distortions of the VDAC-1 barrel and the displacement of particular charged amino acids. We constructed conformational models of the protein voltage response and the pore changes that consistently explain the protein conformations observed at opposite voltage polarities, either in phosphatidylethanolamine or phosphatidylcholine membranes. The submicrosecond VDAC-1 voltage response shows intrinsic structural changes that explain the role of key gating amino acids and support some of the current gating hypotheses. These voltage-dependent protein changes include asymmetric barrel distortion, its interaction with the membrane, and significant displacement of N-α amino acids.