Probing a Complex of Cytochromecand Cardiolipin by Magnetic Circular Dichroism Spectroscopy: Implications for the Initial Events in Apoptosis

Bradley, JM, Silkstone, G, Wilson, MT, Cheesman, MR and Butt, JN (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 Biological Sciences
    Faculty of Science > School of Chemistry
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    Depositing User: Users 2731 not found.
    Date Deposited: 10 Jan 2012 14:32
    Last Modified: 11 Apr 2019 14:35
    URI: https://ueaeprints.uea.ac.uk/id/eprint/36053
    DOI: 10.1021/ja209144h

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