Ubiquinone-0, menaquinone-0, and 2,3,5-trimethyl-1,4-benzoquinone were site-specifically bound to free cysteine of proteins (yeast iso-1 cytochrome c as a model protein) through thioether bond formation. Model thioether quinone conjugates showed unexpected reactivity to cysteine of proteins as their parent quinones by thiol addition-elimination reaction. Cyclic voltammetry studies of the model compounds showed only minor differences in their redox potentials as compared to their parent quinones. Thioether ligation provides a general, simple, and fast method to construct model quinone protein systems. In addition, these studies also contribute to the understanding of biological activities, toxicity, and anti-cancer mechanism of quinones and thioether quinone adducts.
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http://dx.doi.org/10.1021/ja050974x | DOI Listing |
Nanoscale
January 2025
Department of Chemistry, Federal University of São Paulo (UNIFESP), Diadema, SP, Brazil.
This study aims to use superparamagnetic iron oxide nanoparticles (SPIONs), specifically magnetite (FeO), to deliver deflazacort (DFZ) and ibuprofen (IBU) to Duchenne muscular dystrophy-affected (DMD) mouse muscles using an external magnetic field. The SPIONs are synthesized by the co-precipitation method, and their surfaces are functionalized with L-cysteine to anchor the drugs, considering that the cysteine on the surface of the SPIONs in the solid state dimerizes to form the cystine molecule, creating the FeO-(Cys)-DFZ and FeO-(Cys)-IBU systems for tests. The FeO nanoparticles (NPs) were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and magnetic measurements.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Laboratory of Neurobiology, Department of Neurology, Poznan, Poland.
Background: Alzheimer's disease (AD) is characterized by an acquired, progressive impairment of cognitive functions. The pathogenesis of this disease remains unknown. It is explained based on the following theories: amyloid cascade, inflammation, vascular, and infection hypothesis.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Neuroscience Graduate Program, Weill Cornell Medicine, New York, NY, USA.
Background: Mitochondrial reactive oxygen species (mROS), such as superoxide and hydrogen peroxide (HO), are implicated in aging-associated neurological disorders, including Alzheimer's Disease and frontotemporal dementia. Mitochondrial complex III of the respiratory chain has the highest capacity for mROS production and generates mROS toward the cytosol, poising it to regulate intracellular signaling and disease mechanisms. However, the exact triggers of complex III-derived ROS (CIII-ROS), its downstream molecular targets, and its functional roles in dementia-related pathogenesis remain unclear.
View Article and Find Full Text PDFJ Biomol Struct Dyn
January 2025
Department of Agricultural Convergence Technology, Jeonbuk National University, Jeonju, Republic of Korea.
Cryptosporidiosis is an infection induced by the single-celled protozoan Cryptosporidium parasite. This parasite commonly infects the intestines of humans and animals, leading to gastrointestinal symptoms such as diarrhea, stomach cramps, nausea, and vomiting. Cryptopain protein, a type of cysteine protease found in the genome of plays an important role in cell invasion and its survival.
View Article and Find Full Text PDFFront Chem Biol
August 2024
Center for Structure-based Drug Design and Development, Department of Pharmaceutical Sciences, Concordia University Wisconsin, Mequon, WI, United States.
Introduction: Dual specific phosphatases (DUSPs) are mitogen-activated protein kinase (MAPK) regulators, which also serve as drug targets for treating various vascular diseases. Previously, we have presented mechanistic characterizations of DUSP5 and its interaction with pERK, proposing a dual active site.
Methods: Herein, we characterize the interactions between the DUSP5 phosphatase domain and the pT-E-pY activation loop of ERK2, with specific active site assignments.
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