The removal of phospholipids bound to Tween 20 solubilized bovine cytochrome bc1, especially the tightly bound cardiotipin, perturbs the environment of the low potential cytochrome b566 .and results in the autoreduction of cytochrome c1. The perturbation in cytochrome b 566 is manifested by a hypsochromic effect (blue shift). The autoreduced cytochrome c1 can be oxidized and re-reduced indicating that it is a reversible process. The molecular environment of the high potential cytochrome b562 is largely unperturbed. Inhibition of cytochrome be1 with antimycin-A before delipidation prevents the perturbation in cytochrome b 566 but does not completely abolish the autoreduction of cytochrome c1. Delipidated (cytochrome bc1 contains all eleven subunits though the relative content of subunit V, VII and XI have decreased by 30-60%. Analysis of the tightly bound anionic phospholipid cardiolipin by silicic acid-HPLC indicates that less than 0.05 molecules of cardiolipin remains bound to cytochrome bc1. Moreover, delipidated cytochrome bc 1 is still antimycin sensitive indicating that little structural perturbations have occurred near the environment of the high potential cytochrome b562. Thus, cardiolipin depleted Tween 20 solubilized bovine cytochrome bet has been prepared in a state where structural perturbations have been minimized.
|Original language||English (US)|
|State||Published - 1997|
ASJC Scopus subject areas
- Molecular Biology