Functional dynamics in the voltage-dependent anion channel

Proc Natl Acad Sci U S A. 2010 Dec 28;107(52):22546-51. doi: 10.1073/pnas.1012310108. Epub 2010 Dec 10.

Abstract

The voltage-dependent anion channel (VDAC), located in the outer mitochondrial membrane, acts as a gatekeeper for the entry and exit of mitochondrial metabolites. Here we reveal functional dynamics of isoform one of VDAC (VDAC1) by a combination of solution NMR spectroscopy, Gaussian network model analysis, and molecular dynamics simulation. Micro- to millisecond dynamics are significantly increased for the N-terminal six β-strands of VDAC1 in micellar solution, in agreement with increased B-factors observed in the same region in the bicellar crystal structure of VDAC1. Molecular dynamics simulations reveal that a charge on the membrane-facing glutamic acid 73 (E73) accounts for the elevation of N-terminal protein dynamics as well as a thinning of the nearby membrane. Mutation or chemical modification of E73 strongly reduces the micro- to millisecond dynamics in solution. Because E73 is necessary for hexokinase-I-induced VDAC channel closure and inhibition of apoptosis, our results imply that micro- to millisecond dynamics in the N-terminal part of the barrel are essential for VDAC interaction and gating.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Crystallography, X-Ray
  • Dicyclohexylcarbodiimide / chemistry
  • Dimyristoylphosphatidylcholine / chemistry
  • Humans
  • Ion Channel Gating / physiology*
  • Kinetics
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Magnetic Resonance Spectroscopy / methods*
  • Mice
  • Mitochondrial Membranes / chemistry
  • Mitochondrial Membranes / metabolism
  • Models, Molecular
  • Molecular Dynamics Simulation*
  • Mutation, Missense
  • Protein Structure, Secondary
  • Solutions
  • Time Factors
  • Voltage-Dependent Anion Channel 1 / chemistry
  • Voltage-Dependent Anion Channel 1 / genetics
  • Voltage-Dependent Anion Channel 1 / physiology*

Substances

  • Lipid Bilayers
  • Solutions
  • Dicyclohexylcarbodiimide
  • Voltage-Dependent Anion Channel 1
  • Dimyristoylphosphatidylcholine