Soft perforation of cardiolipincontaining planar

Authors: V F Antonov M N Puchkov E A Korepanova O Yu Nemchenko V Borodulin

Publish Date: 2014/08/13

Volume: 43, Issue: 10-11, Pages: 469-476

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Abstract

The release of cytochrome c cyt c from mitochondria is responsible for initiation of cell apoptosis Although extramitochondrial proteins are thought to initiate this release the exact mechanism remains unclear Cyt c binds to and penetrates lipid bilayer membranes of specific phospholipid cardiolipin CL contained in mitochondria We present here the experimental results of monitoring planar BLM pBLM from mixtures of azolectin and of CL 4/1 by moles by triangle voltage pulses of 100 mV in amplitude and frequency of 2 Hz The BLM were modified by a successive addition of cyt c and of H2O2 in water solution It is shown that the addition of cyt c alone leads to a stepwise increase in the ionic conductance of the pBLM indicating the appearance of transmembrane pores Pore lifetimes then reached several seconds at an average pore diameter of ~2 nm Current–voltage characteristics were then linear and passed through the origin which is characteristic for broad nonselective ion pores Subsequent addition of H2O2 caused a dramatic increase in transmembrane current at retention of average pore size constant Observed increase in membrane current is due to growth of a number of pores in an open state We suggest that hydrogen peroxide in the presence of cyt c promotes a peroxidation of membrane phospholipids to form lysolipids the embedding of which stabilizes the edge of the pore and the surface of lipid bilayer

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