Isolation and characterization of the mitochondrial channel, VDAC, from the insect Heliothis virescens.
A 31 kDa voltage-dependent anion-selective channel (VDAC) protein was purified from the insect Heliothis virescens (tobacco budworm, denoted TBW) using an alkali extraction and filtration procedure and was characterized by SDS-PAGE, amino acid sequencing, biophysical properties and immunocytochemistry. The N-terminal sequence has highest identity with VDACs from mammals (50-66%) followed by plants (34-41%) and lower eukaryotes (30-34%). Reconstitution in planar phospholipid membranes yielded properties typical of VDACs from other organisms including a single-channel conductance of 4.1 nS (in 1 M KCl), closure in response to positive and negative transmembrane voltage, and a reversal potential of 11.8 mV indicating anion selectivity in the open state. A polyclonal antiserum (R19) raised against gel-purified 31 kDa protein specifically labelled mitochondria and mitochondrial outer membranes in TBW flight muscle by light and electron microscope immunocytochemistry.
Ryerse
J
J
Department of Pathology, St. Louis University Health Sciences Center, MO 63104, USA. ryersejs@slu.edu
Colombini
M
M
Hagerty
T
T
Nagel
B
B
Liu
T T
TT
D000595:Amino Acid Sequence; D000818:Animals; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification*; D008928:Mitochondria / Q000737:chemistry*; D008969:Molecular Sequence Data; D009036:Moths / Q000737:chemistry*; D009132:Muscles / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000302:isolation & purification*; D018272:Porins; D050994:Voltage-Dependent Anion Channels
D029721:Drosophila Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D018272:Porins; D050994:Voltage-Dependent Anion Channels; C494761:porin protein, Drosophila