J. Ryerse et al., ISOLATION AND CHARACTERIZATION OF THE MITOCHONDRIAL CHANNEL, VDAC, FROM THE INSECT HELIOTHIS-VIRESCENS, Biochimica et biophysica acta. Biomembranes, 1327(2), 1997, pp. 193-203
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 char
acterized by SDS-PAGE, amino acid sequencing, biophysical properties a
nd immunocytochemistry. The N-terminal sequence has highest identity w
ith VDACs from mammals (50-66%) followed by plants (34-41%) and lower
eukaryotes (30-34%). Reconstitution in planar phospholipid membranes y
ielded properties typical of VDACs from other organisms including a si
ngle-channel conductance of 4.1 nS (in 1 M KCl), closure in response t
o positive and negative transmembrane voltage, and a reversal potentia
l of 11.8 mV indicating anion selectivity in the open state. A polyclo
nal antiserum (R19) raised against gel-purified 31 kDa protein specifi
cally labelled mitochondria and mitochondrial outer membranes in TBW f
light muscle by light and electron microscope immunocytochemistry. (C)
1997 Elsevier Science B.V.