The ChaC family of γ-glutamyl cyclotransferases is required for Leishmania to switch to a slow growth state and for long-term survival of the parasite

Power of Dopamine: Multifunctional Compound Assisted Conversion of the Most Risk Factor into Therapeutics of Alzheimer's Disease

In Alzheimer's disease (AD), reactive oxygen species (ROS) plays a crucial role, which is produced from molecular oxygen with extracellular deposited amyloid-β (Aβ) aggregates through the reduction of a Cu2+ ion. In the presence of a small amount of redox-active Cu2+ ion, ROS is produced by the Aβ-Cu2+ complex as Aβ peptide alone is unable to generate excess ROS. Therefore, Cu2+ ion chelators are considered promising therapeutics against AD. Here, we have designed and synthesized a series of Schiff base derivatives (SB) based on 2-hydroxy aromatic aldehyde derivatives and dopamine. These SB compounds contain one copper chelating core, which captures the Cu2+ ions from the Aβ-Cu2+ complex. Thereby, it inhibits copper-induced amyloid aggregation as well as amyloid self-aggregation. It also inhibits copper-catalyzed ROS production through sequestering of Cu2+ ions. The uniqueness of our designed ligands has the dual property of dopamine, which not only acts as a ROS scavenger but also chelates the copper ion. The crystallographic analysis proves the power of the dopamine unit. Therefore, dual exploration of dopamine core can be considered as potential therapeutics for future AD treatment.

Mitochondrial Glutathione in Cellular Redox Homeostasis and Disease Manifestation

Mitochondria are critical for providing energy to maintain cell viability. Oxidative phosphorylation involves the transfer of electrons from energy substrates to oxygen to produce adenosine triphosphate. Mitochondria also regulate cell proliferation, metastasis, and deterioration. The flow of electrons in the mitochondrial respiratory chain generates reactive oxygen species (ROS), which are harmful to cells at high levels. Oxidative stress caused by ROS accumulation has been associated with an increased risk of cancer, and cardiovascular and liver diseases. Glutathione (GSH) is an abundant cellular antioxidant that is primarily synthesized in the cytoplasm and delivered to the mitochondria. Mitochondrial glutathione (mGSH) metabolizes hydrogen peroxide within the mitochondria. A long-term imbalance in the ratio of mitochondrial ROS to mGSH can cause cell dysfunction, apoptosis, necroptosis, and ferroptosis, which may lead to disease. This study aimed to review the physiological functions, anabolism, variations in organ tissue accumulation, and delivery of GSH to the mitochondria and the relationships between mGSH levels, the GSH/GSH disulfide (GSSG) ratio, programmed cell death, and ferroptosis. We also discuss diseases caused by mGSH deficiency and related therapeutics.

Importance of aspartate 4 in the Mg2+ dependent regulation of Leishmania major PAS domain-containing phosphoglycerate kinase

Magnesium is an important divalent cation for the regulation of catalytic activity. Recently, we have described that the Mg2+ binding through the PAS domain inhibits the phosphoglycerate kinase (PGK) activity in PAS domain-containing PGK from Leishmania major (LmPAS-PGK) at neutral pH 7.5, but PGK activity is derepressed at acidic pH 5.5. The acidic residue within the PAS domain of LmPAS-PGK is expected to bind the cofactor Mg2+ ion at neutral pH, but which specific acidic residue(s) is/are responsible for the Mg2+ binding is still unknown. To identify the residues, we exploited mutational studies of all acidic (twelve Asp/Glu) residues in the PAS domain for plausible Mg2+ binding. Mg2+ ion-dependent repression at pH 7.5 is withdrawn by substitution of Asp-4 with Ala, whereas other acidic residue mutants (D16A, D22A, D24A, D29A, D43A, D44A, D60A, D63A, D77A, D87A, and E107A) showed similar features compared to the wild-type protein. Fluorescence spectroscopic studies and isothermal titration calorimetry analysis showed that the Asp-4 is crucial for Mg2+ binding in the absence of both PGK's substrates. These results suggest that Asp-4 residue in the regulatory (PAS) domain of wild type enzymes is required for Mg2+ dependent repressed state of the catalytic PGK domain at neutral pH.