Rajagopal, Badri S and Silkstone, Gary G and Nicholls, Peter and Wilson, Michael T and Worrall, Jonathan AR (2012) An investigation into a cardiolipin acyl chain insertion site in cytochrome c. Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1817 (5). pp. 780-791. DOI https://doi.org/10.1016/j.bbabio.2012.02.010
Rajagopal, Badri S and Silkstone, Gary G and Nicholls, Peter and Wilson, Michael T and Worrall, Jonathan AR (2012) An investigation into a cardiolipin acyl chain insertion site in cytochrome c. Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1817 (5). pp. 780-791. DOI https://doi.org/10.1016/j.bbabio.2012.02.010
Rajagopal, Badri S and Silkstone, Gary G and Nicholls, Peter and Wilson, Michael T and Worrall, Jonathan AR (2012) An investigation into a cardiolipin acyl chain insertion site in cytochrome c. Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1817 (5). pp. 780-791. DOI https://doi.org/10.1016/j.bbabio.2012.02.010
Abstract
Mitochondrial cytochrome c associates with the phosphoplipid cardiolipin (CL) through a combination of electrostatic and hydrophobic interactions. The latter occurs by insertion into cytochrome c of an acyl chain, resulting in the dissociation of the axial Met-80 heme-iron ligand. The resulting five coordinate cytochrome c/CL complex has peroxidatic properties leading to peroxidation of CL and dissociation of the complex. These events are considered to be pre-apoptotic and culminate with release of cytochrome c from the mitochondria into the cytoplasm. Two distinct surface regions on cytochrome c have been suggested to mediate CL acyl chain insertion and this study has probed one of these regions. We have constructed a series of alanine mutants aimed at disrupting a surface cleft formed between residues 67-71 and 82-85. The physicochemical properties, peroxidase activity, CL binding, and kinetics of carbon monoxide (CO) binding to the ferrous cytochrome c/CL complex have been assessed for the individual mutants. Our findings reveal that the majority of mutants are capable of binding CL in the same apparent stoichiometry as the wild-type protein, with the extent to which the Met-80 ligand is bound in the ferrous cytochrome c/CL complex being mutant specific at neutral pH. Mutation of the species conserved Arg-91 residue, that anchors the cleft, results in the greatest changes to physicochemical properties of the protein leading to a change in the CL binding ratio required to effect structural changes and to the ligand-exchange properties of the ferrous cytochrome c/CL complex. © 2012 Elsevier B.V. © 2012 Elsevier B.V. All rights reserved.
Item Type: | Article |
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Uncontrolled Keywords: | Cytochrome c; Phospholipids; Cardiolipin; Apoptosis; Peroxidase; Ligand binding |
Subjects: | Q Science > QH Natural history > QH301 Biology |
Divisions: | Faculty of Science and Health Faculty of Science and Health > Life Sciences, School of |
SWORD Depositor: | Unnamed user with email elements@essex.ac.uk |
Depositing User: | Unnamed user with email elements@essex.ac.uk |
Date Deposited: | 13 Mar 2013 22:24 |
Last Modified: | 30 Oct 2024 20:13 |
URI: | http://repository.essex.ac.uk/id/eprint/5849 |