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The interaction between cytochrome c and cardiolipin is a relevant process in the mitochondrial redox homeostasis, playing roles in the mechanism of electron transfer to cytochrome c oxidase and also modulating cytochrome c conformation, reactivity and function. Peroxynitrite is a widespread nitrating agent formed in mitochondria under oxidative stress conditions, and can result in the formation of tyrosine nitrated cytochrome c. Some of the nitro-cytochrome c species undergo conformational changes at physiological pH and increase its peroxidase activity. In this work we evaluated the influence of cardiolipin on peroxynitrite-mediated cytochrome c nitration yields and site-specificity. Our results show that cardiolipin enhances cytochrome c nitration by peroxynitrite and targets it to heme-adjacent Tyr67. Cytochrome c nitration also modifies the affinity of protein with cardiolipin. Using a combination of experimental techniques and computer modeling, it is concluded that structural modifications in the Tyr67 region are responsible for the observed changes in protein-derived radical and tyrosine nitration levels, distribution of nitrated proteoforms and affinity to cardiolipin. Increased nitration of cytochrome c in presence of cardiolipin within mitochondria and the gain of peroxidatic activity could then impact events such as the onset of apoptosis and other processes related to the disruption of mitochondrial redox homeostasis.
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http://dx.doi.org/10.1016/j.abb.2021.108824 | DOI Listing |
ACS Catal
June 2025
Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.
RufO is a unique cytochrome P450 enzyme (CYP) involved in the biosynthesis of rufomycin, an antituberculosis cyclic peptide featuring an unusual nitrated tyrosine. Recent studies have clarified RufO's role in producing ribosomally synthesized and post-translationally modified peptides (RiPPs). Despite growing interest in nitrating enzymes and RiPP biosynthesis, the mechanism by which RufO recognizes and nitrates its pentapeptide substrate, MRYLH, remains poorly understood.
View Article and Find Full Text PDFAntioxidants (Basel)
February 2025
Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, São Paulo 04041-001, Brazil.
Mitochondrial diseases are complex disorders caused by nuclear or mitochondrial DNA mutations, leading to oxidative phosphorylation deficiency and excessive production of reactive oxygen species (ROS). While ROS have been well established in the pathogenesis of these diseases, the role of reactive nitrogen species (RNS) remains unclear. In this study, we performed a quantitative analysis of muscle fibers to investigate the relationship between protein nitration and mitochondrial abnormalities (mitochondrial proliferation and cytochrome-c oxidase (COX) deficiency) and factors like genotype, muscle damage, and age.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, United States.
The cytochrome P450 homolog, TxtE, efficiently catalyzes the direct and regioselective aromatic nitration of the indolyl moiety of L-tryptophan to 4-nitro-L-tryptophan, using nitric oxide (NO) and dioxygen (O) as co-substrates. Pathways for such direct and selective nitration of heteroaromatic motifs present platforms for engineering new nitration biocatalysts for pharmacologically beneficial targets, among a medley of other pivotal industrial applications. Precise mechanistic details concerning this pathway are only weakly understood, albeit a heme iron(III)-peroxynitrite active species has been postulated.
View Article and Find Full Text PDFDrug Metab Dispos
September 2024
Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia
Since his graduate studies on alcohol induction of a novel cytochrome P450 (P450) enzyme, through his postdoctoral work on hormonal regulation of sexually differentiated cytochrome P450s (P450s), the author has maintained an interest in the regulation of drug metabolizing enzymes. This article is a recounting of his scientific career and focuses on his laboratory's work on inflammatory regulation of P450 enzymes that formed the basis for the Bernard B. Brodie Award.
View Article and Find Full Text PDFInt J Mol Sci
April 2024
Department of Radiology, Innlandet Trust Hospital, Gjøvik Hospital, 2819 Gjøvik, Norway.
Platinum-containing chemotherapeutic drugs are efficacious in many forms of cancer but are dose-restricted by serious side effects, of which peripheral neuropathy induced by oxidative-nitrosative-stress-mediated chain reactions is most disturbing. Recently, hope has been raised regarding the catalytic antioxidants mangafodipir (MnDPDP) and calmangafodipir [CaMn(DPDP); PledOx], which by mimicking mitochondrial manganese superoxide dismutase (MnSOD) may be expected to overcome oxaliplatin-associated chemotherapy-induced peripheral neuropathy (CIPN). Unfortunately, two recent phase III studies (POLAR A and M trials) applying CaMn(DPDP) in colorectal cancer (CRC) patients receiving multiple cycles of FOLFOX6 (5-FU + oxaliplatin) failed to demonstrate efficacy.
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