Functional diversity of YbbN/CnoX proteins: Insights from a comparative analysis of three thioredoxin-like oxidoreductases from Pseudomonas aeruginosa, Xylella fastidiosa and Escherichia coli.

YbbN/CnoX are proteins that display a Thioredoxin (Trx) domain linked to a tetratricopeptide domain. YbbN from Escherichia coli (EcYbbN) displays a co-chaperone (holdase) activity that is induced by HOCl. Here, we compared EcYbbN with YbbN proteins from Xylella fastidiosa (XfYbbN) and from Pseudomonas aeruginosa (PaYbbN).

Antioxidant cytochrome c-like activity of para-MnTMPyP.

Manganese porphyrins are well-known protectors against the deleterious effects of pro-oxidant species such as superoxide ions and hydrogen peroxide. The present study investigated the antioxidant cytochrome c-like activities of Mn(III)TMPyP [meso-tetrakis (4-N-methyl pyridinium) porphyrin] against superoxide ion and hydrogen peroxide that remained unexplored for this porphyrin. The association of TMPyP with a model of the inner mitochondrial membrane, cardiolipin (CL)-containing liposomes, shifted +30 mV vs.

Redox modulation of thimet oligopeptidase activity by hydrogen peroxide.

Thimet oligopeptidase (EC 3.4.24.

Thiosemicarbazone p-Substituted Acetophenone Derivatives Promote the Loss of Mitochondrial Δψ, GSH Depletion, and Death in K562 Cells.

A series of thiosemicarbazone (TSC) p-substituted acetophenone derivatives were synthesized and chemically characterized. The p-substituents appended to the phenyl group of the TSC structures were hydrogen, fluor, chlorine, methyl, and nitro, producing compounds named TSC-H, TSC-F, TSC-Cl, TSC-Me, and TSC-NO2, respectively. The TSC compounds were evaluated for their capacity to induce mitochondrial permeability, to deplete mitochondrial thiol content, and to promote cell death in the K562 cell lineage using flow cytometry and fluorescence microscopy.

Effects of trichlorotelluro-dypnones on mitochondrial bioenergetics and their relationship to the reactivity with protein thiols.

The effect of four trichlorotelluro-dypnones, named compounds 1, 2, 3, and 4, on the bioenergetics of isolated rat liver mitochondria (RLM) and cells was investigated. In a dose-dependent manner, the studied organotelluranes promoted Ca(2+)-dependent mitochondrial swelling inhibited by cyclosporine A and were associated with a decrease of the total mitochondrial protein thiol content. These effects characterize the opening of the classical mitochondrial permeability transition pore.

Inhibition of cytoplasmic p53 differentially modulates Ca(2+) signaling and cellular viability in young and aged striata.

The p53 protein, a transcription factor with many gene targets, can also trigger apoptosis in the cytoplasm. The disruption of cell homeostasis, such as Ca(2+) signaling and mitochondrial respiration, contributes to the loss of viability and ultimately leads to cell death. However, the link between Ca(2+) signaling and p53 signaling remains unclear.

Towards the mechanisms involved in the antioxidant action of MnIII [meso-tetrakis(4-N-methyl pyridinium) porphyrin] in mitochondria.

Aerobic organisms are afforded with an antioxidant enzymatic apparatus that more recently has been recognized to include cytochrome c, as it is able to prevent hydrogen peroxide generation by returning electrons from the superoxide ion back to the respiratory chain. The present study investigated the glutathione peroxidase (GPx), superoxide dismutase (SOD) and cytochrome c-like antioxidant activities of para Mn(III)TMPyP in isolated rat liver mitochondria (RLM) and mitoplasts. In RLM, Mn(III)TMPyP decreased the lipid-peroxide content associated with glutathione (GSH) depletion consistent with the use of GSH as a reducing agent for high valence states of Mn(III)TMPyP.

Molecular interactions and structure of a supramolecular arrangement of glucose oxidase and palladium nanoparticles.

This paper presents studies about the molecular interactions and redox processes involved in the formation of palladium nanoparticles associated to glucose oxidase (GOx-PdNPs) in a supramolecular arrangement. The synthesis occurs in two steps, the Pd reduction and the formation of the 80 nm sized supramolecular aggregates containing multiples units of GOx associated to 3.5 nm sized PdNPs.

Specific effects of reactive thiol drugs on mitochondrial bioenergetics.

In this minireview, the more recent findings about the effects of peculiar reactive thiol drugs on mitochondria are presented. These include the following compounds: metallo meso-tetrakis porphyrins, palladacycles, telluranes and phenothiazines. Metallo meso-tetrakis porphyrins can exhibit both beneficial and deleterious effects on mitochodria that are modulated by the central metal, cell location, and availability of axial ligands.

Characterization of hydrophobic interaction and antioxidant properties of the phenothiazine nucleus in mitochondrial and model membranes.

The antioxidant properties of the phenothiazine nucleus (PHT) associated with mitochondrial membranes and liposomes were investigated. PHT exhibited hydrophobic interaction with lipid bilayers, as shown by the quenching of excited states of 1-palmitoyl-2[10-pyran-1-yl)]-decanoyl-sn-glycero-3-phophocholine (PPDPC) incorporated in phosphatidylcholine/phosphatidylethanolamine/cardiolipin liposomes, observed even in high ionic strength; and by the spectral changes of PHT following the addition of mitochondrial membranes. Inserted into bilayers, 5 microM PHT was able to protect lipids and cytochrome c against pro-oxidant agents and exhibited spectral changes suggestive of oxidative modifications promoted by the trapping of the reactive species.