Bradley, Justin M., Silkstone, Gary, Wilson, Michael T., Cheesman, Myles R. and Butt, Julea N. (2011) Probing a Complex of Cytochromecand Cardiolipin by Magnetic Circular Dichroism Spectroscopy: Implications for the Initial Events in Apoptosis. Journal of the American Chemical Society, 133 (49). pp. 19676-19679. ISSN 0002-7863

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Abstract

Oxidation of cardiolipin (CL) by its complex with cytochrome c (cyt c) plays a crucial role in triggering apoptosis. Through a combination of magnetic circular dichroism spectroscopy and potentiometric titrations, we show that both the ferric and ferrous forms of the heme group of a CL:cyt c complex exist as multiple conformers at a physiologically relevant pH of 7.4. For the ferric state, these conformers are His/Lys- and His/OH–-ligated. The ferrous state is predominantly high-spin and, most likely, His/–. Interconversion of the ferric and ferrous conformers is described by a single midpoint potential of -80 ± 9 mV vs SHE. These results suggest that CL oxidation in mitochondria could occur by the reaction of molecular oxygen with the ferrous CL:cyt c complex in addition to the well-described reaction of peroxides with the ferric form.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Chemistry Faculty of Science > School of Biological Sciences
Depositing User:	Users 2731 not found.
Date Deposited:	10 Jan 2012 14:32
Last Modified:	17 Sep 2020 23:29
URI:	https://ueaeprints.uea.ac.uk/id/eprint/36053
DOI:	10.1021/ja209144h

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