Patch clamping VDAC in liposomes containing whole mitochondrial membranes |
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Authors: | Uwe R Wunder Marco Colombini |
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Institution: | (1) Laboratories of Cell Biology, Department of Zoology, University of Maryland, 20742 College Park, Maryland;(2) Present address: Abteilung Biochemie, Universität Witten/Herdecke, Stockumer Str. 10, D-5810 Witten, Germany |
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Abstract: | Summary Whole mitochondrial membranes isolated fromNeurospora crassa were reconstituted into liposomes and patch clamped. Clear activity characteristic of the mitochondrial channel VDAC was found, namely: open state conductance of 650 pS (in 150mm KCl, 1mm CaCl2, 20mm HEPES, pH 7.2), voltage-dependent closure at both positive and negative potentials, change in conductance upon channel closure of about 450 pS in response to negative and positive potentials, and increased voltage dependence in the presence of König's polyanion. This is the first clear demonstration of VDAC single channels using the patch-clamp technique, even though others used this method before to study whole mitochondrial membranes and liposomes containing mitochondrial proteins. We also found one other channel with a conductance change of about 120 pS. |
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Keywords: | ion channels mitochondrial membranes voltage dependence VDAC Neurospora crassa |
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