The enzyme O-acetylserine sulfhydrylase participates in the biosynthesis of l-cysteine in bacteria and plants. The structure of isoenzyme B (CysM) from Escherichia coli was established in a hexagonal crystal form at 2.7 A resolution (wild-type) and in a merohedrally twinned tetragonal crystal form at 2.1 A resolution (surface mutant). Structural superpositions revealed the variations with respect to isoenzyme A (CysK) and explained the different substrate specificities. A geometric model of the reaction catalyzed by CysM is proposed. Both isoenzymes are used for the production of l-amino acid derivatives as building blocks for the synthesis of peptides and peptidomimetic drugs. Since the structure of CysM revealed a remarkable main chain variation at the active center, it constitutes a further starting point for engineering mutants with novel substrate specificities.
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http://dx.doi.org/10.1021/bi050485+ | DOI Listing |
Andrology
January 2025
Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey.
Background: Androgen deprivation is associated with erectile dysfunction (ED). In different animal models, sulfur dioxide (SO) donors NaSO and NaHSO reduced oxidative stress, fibrosis, and inflammation which contribute to the pathogenesis of androgen deprivation-induced ED, however the effect of SO donors on ED in castrated rats were not known.
Objective: To investigate the therapeutic effect of SO donors, NaSO/NaHSO, on ED in castrated rat model.
Biomolecules
November 2024
Department of Biology, Washington University, St. Louis, MO 63146, USA.
Mitochondrial holocytochrome c synthase (HCCS) is an essential protein in assembling cytochrome c (cyt c) of the electron transport system. HCCS binds heme and covalently attaches the two vinyls of heme to two cysteine thiols of the cyt c CXXCH motif. Human HCCS recognizes both cyt c and cytochrome c of complex III (cytochrome bc).
View Article and Find Full Text PDFCommun Biol
January 2025
Georgia Cancer Center, Augusta University, Augusta, GA, 30912, USA.
The transsulfuration (TSS) pathway is an alternative source of cysteine for glutathione synthesis. Little of the TSS pathway in antioxidant capacity in sickle cell disease (SCD) is known. Here, we evaluate the effects of TSS pathway activation through cystathionine beta-synthase (CBS) to attenuate reactive oxygen species (ROS) and ferroptosis stresses in SCD.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India. Electronic address:
Biofilm formation is a key adaptive response of marine bacteria towards stress conditions. The protective mechanisms of biofilm matrixome proteins against heavy metals (Pb and Cd) induced oxidative damage in the marine bacterium Bacillus stercoris GST-03 was investigated. Exposure to heavy metals resulted in significant changes in cell morphology, biofilm formation, and matrixome composition.
View Article and Find Full Text PDFFood Chem
December 2024
College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China; The International Peace Maternity and Child Health Hospital, School of Medicine. Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address:
Hydrogen sulfide (HS) is an metabolic product of tuna during the spoilage, and relationship between HS and tuna quality has not been specifically studied. This study detected changes in HS content, HS precursor substances, and related enzymes based on the formation pathway of HS. HS content increased of tuna resulted in significant increases in contents of cystathionine β-synthase, cystathionine γ-lyase, 3-mercapto pyruvate sulfotransferase, cysteine aminotransferase and methionine, while content of cysteine decreased which provided HS formation.
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