Peroxidase Complexes of Cytochrome C with Anionic Lipids: Structural Pre-Requisites, Mechanisms, and Cytotoxic Effects

Details

• Personal Author:
  Basova LV ; Bayir H ; Belikova NA ; Glumac A ; Jiang J ; Kagan VE ; Kapralov AA ; Martin, Jennifer E. ; Tyurin VA ; Tyurina YY ; Vlasova II
• Description:
  Interaction of cytochrome c (cyt c) with a mitochondria-specific cardiolipin (CL) confers peroxidase activity on the protein resulting in selective CL oxidation and release of proapoptotic factors. Because the complex cyt c/CL is stabilized by a combination of electrostatic and hydrophobic interactions, we determined the extent to which other anionic lipids - phosphatidic acid (PA), phosphatidylserine (PS), phosphatidylinositolphosphates (PIP), and phosphatidylcholine (PC) as a control - are effective in inducing the peroxidase activity of cyt c. EPR spectroscopy of nitrosylated cyt c, optical spectroscopy and measurements of tryptophan fluorescence demonstrated that cyt c interaction with anionic lipids induced protein unfolding accompanied by an exchange and loss of axial ligands of heme iron so that cyt c heme became more accessible for the interaction with small molecules like NO or H2O2. Using several peroxidase substrates we showed that all anionic lipids activated peroxidase activity of cyt c in a dose-dependent manner with the efficiency decreasing in the row: CL=PA>PIP2>PIP3>PS. Recombination of protein-derived radicals formed in peroxidase reaction caused oligomerization of cyt c and formation of protein-lipid aggregates detectable by PAGE and Western blotting. In line with this, Western blotting revealed the formation of cyt c aggregates after its incubation in the presence of H2O2 with membrane (but not cytosolic S-100) fraction of brain homogenates. Oxidation products of anionic lipids were detected after induction of apoptosis in HeLa cells and mouse embryonic wild type cells but not in cyt c-deficient cells. Overall, our study identified anionic lipids as physiologically relevant regulators of peroxidase activity of cyt c in mitochondria and other cell compartments, particularly during apoptosis. [Description provided by NIOSH]
• Subjects:
  Animals Biomarkers Chemistry Occupational Health Safety
• Keywords:
  Animal-studies Cell-alteration Cell-damage Cellular-reactions Chemical-analysis Chemical-composition Chemical-indicators Chemical-synthesis Physiological-chemistry Physiological-effects Physiological-response

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• ISSN:
  1096-6080
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  61
• Volume:
  96
• Issue:
  1
• NIOSHTIC Number:
  nn:20031898
• Citation:
  Toxicologist 2007 Mar; 96(1):61
• Federal Fiscal Year:
  2007
• Performing Organization:
  University of Pittsburgh at Pittsburgh
• Peer Reviewed:
  False
• Start Date:
  20050701
• End Date:
  20160630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:fe770e869a824b8ae9dd3feb1cfa278ba9d73785740f3cd6a66f4ad7b1bc656a1f8d8f3431a8365cc35c4a7ab6116af6769a8f7ebd6e7a3c1b9da68d7e926376
• Download URL:
  https://stacks.cdc.gov/view/cdc/186010/cdc_186010_DS1.pdf
• File Type:
  [PDF - 518.39 KB ]