Peroxidase Activity and Structural Transitions of Cytochrome C Bound to Cardiolipin-Containing Membranes

Details

• Personal Author:
  Basova LV ; Belikova NA ; Kagan VE ; Kapralov AA ; Kurnikov IV ; Osipov AN ; Peterson J ; Potapovich MV ; Tyurin VA ; Vladimirov YA
• Description:
  During apoptosis, cytochrome c (cyt c) is released from intermembrane space of mitochondria into the cytosol where it triggers the caspase-dependent machinery. We discovered that cyt c plays another critical role in early apoptosis as a cardiolipin (CL)-specific oxygenase to produce CL hydroperoxides required for release of pro-apoptotic factors [Kagan, V. E., et al. (2005) Nat. Chem. Biol. 1, 223-232]. We quantitatively characterized the activation of peroxidase activity of cyt c by CL and hydrogen peroxide. At low ionic strength and high CL/cyt c ratios, peroxidase activity of the CL/cyt c complex was increased >50 times. This catalytic activity correlated with partial unfolding of cyt c monitored by Trp(59) fluorescence and absorbance at 695 nm (Fe-S(Met(80)) band). The peroxidase activity increase preceded the loss of protein tertiary structure. Monounsaturated tetraoleoyl-CL (TOCL) induced peroxidase activity and unfolding of cyt c more effectively than saturated tetramyristoyl-CL (TMCL). TOCL/cyt c complex was found more resistant to dissociation by high salt concentration. These findings suggest that electrostatic CL/cyt c interactions are central to the initiation of the peroxidase activity, while hydrophobic interactions are involved when cyt c's tertiary structure is lost. In the presence of CL, cyt c peroxidase activity is activated at lower H(2)O(2) concentrations than for isolated cyt c molecules. This suggests that redistribution of CL in the mitochondrial membranes combined with increased production of H(2)O(2) can switch on the peroxidase activity of cyt c and CL oxidation in mitochondria-a required step in execution of apoptosis. [Description provided by NIOSH]
• Subjects:
  Energy Metabolism Enzymes Lipids Occupational Health Safety
• Keywords:
  Cell-metabolism Enzyme-activity Lipid-peroxidation Metabolism Oxidation Oxidation-reduction-reactions Pharmacology
• ISSN:
  0006-2960
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  45
• Issue:
  15
• NIOSHTIC Number:
  nn:20030273
• Citation:
  Biochemistry 2006 Apr; 45(15):4998-5009
• Contact Point Address:
  Center for Free Radical and Antioxidant Health and Department of Environmental and Occupational Health, University of Pittsburgh, 100 Technology Drive, Suite 350, Pittsburgh, PA 15219-3130, USA
• CAS Registry Number:
  2,7-Dichlorodihydrofluorescein (CAS RN 106070-31-9) ; Acridine Orange (CAS RN 65-61-2) ; Cytochrome c (CAS RN 9007-43-6) ; DOPC (CAS RN 10015-85-7) ; Etoposide (CAS RN 33419-42-0) ; L-Tryptophan (CAS RN 73-22-3)
• Federal Fiscal Year:
  2006
• Performing Organization:
  University of Pittsburgh at Pittsburgh
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Biochemistry
• End Date:
  20160630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:bee1e56b1bbfcefa4a2f99d22250c6001d6f3eb6862afb5b8b49ff3bd0fec26592667ed8b5bf2286ffd0808131c2e2e158cb656a9b8e417141dc748a1ca0d8fb
• Download URL:
  https://stacks.cdc.gov/view/cdc/190991/cdc_190991_DS1.pdf
• File Type:
  [PDF - 244.62 KB ]