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Pyruvate carboxylase (PC) has important roles in metabolism and is crucial for virulence for some pathogenic bacteria. PC contains biotin carboxylase (BC), carboxyltransferase (CT) and biotin carboxyl carrier protein (BCCP) components. It is a single-chain enzyme in eukaryotes and most bacteria, and functions as a 500 kD homo-tetramer. In contrast, PC is a two-subunit enzyme in a collection of Gram-negative bacteria, with the α subunit containing the BC and the β subunit the CT and BCCP domains, and it is believed that the holoenzyme has αβ stoichiometry. We report here the crystal structures of a two-subunit PC from Methylobacillus flagellatus. Surprisingly, our structures reveal an αβ stoichiometry, and the overall architecture of the holoenzyme is strikingly different from that of the homo-tetrameric PCs. Biochemical and mutagenesis studies confirm the stoichiometry and other structural observations. Our functional studies in Pseudomonas aeruginosa show that its two-subunit PC is important for colony morphogenesis.
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http://dx.doi.org/10.1038/ncomms12713 | DOI Listing |
mSystems
September 2025
Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas, USA.
is a human fungal pathogen that survives and proliferates within phagocytic immune cells. To sustain growth in the nutrient-limited phagosome environment, the pathogenic yeast scavenges available carbon sources, which must be metabolized through central carbon metabolism for respiration and biomass synthesis. However, carbon metabolic pathways operating in the pathogenic yeast phase have not been extensively mapped.
View Article and Find Full Text PDFFEBS Open Bio
September 2025
Department of Biochemistry, State University of Maringá, Maringá, Brazil.
Epigallocatechin-3-gallate (EGCG), the main catechin in green tea, is associated with antidiabetic and anti-obesity effects, although its acute hepatic actions remain unclear. We investigated short-term effects of EGCG (10-500 μm) using isolated perfused rat livers and complementary assays in mitochondrial, microsomal, and cytosolic fractions. EGCG markedly inhibited gluconeogenesis from lactate (up to 52%), glycerol (33%), and alanine (47%), while it stimulated glycolysis, glycogenolysis, and oleic acid oxidation (+42% total ketone bodies).
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
July 2025
Jiangxi Province Key Laboratory of Traditional Chinese Medicine Etiopathogenisis & Research Center for Differentiation and Development of Traditional Chinese Medicine Basic Theory, Jiangxi University of Chinese Medicine Nanchang 330004, China.
This study aims to investigate the in vitro mechanisms underlying the beneficial effects of puerarin on hepatic insulin resistance(IR) based on the carbohydrate response element-binding protein(ChREBP)/peroxisome proliferator-activated receptor(PPAR)α/PPARγ axis involved in glucose and lipid metabolism. An IR-HepG2 cell model was established by treating cells with dexamethasone for 48 h, and the cells were then treated with 10, 20, and 40 μmol·L~(-1) puerarin for 24 h. Glucose levels and output in the extracellular fluid were measured by the glucose oxidase method, while cell viability was assessed by the cell counting kit-8(CCK-8) assay.
View Article and Find Full Text PDFPlant Cell Rep
September 2025
Key Laboratory of Germplasm Innovation for the Upper Reaches of the Yangtze River, Ministry of Agriculture and Rural Affairs, Chongqing, 400715, China.
The gene ZmDof08, which underlies the yellow-green leaf mutant phenotype in maize, enhances the activity of key enzymes involved in C photosynthesis, leading to a significant improvement in photosynthetic efficiency. Improving the photosynthetic efficiency of maize to increase its yield has long been a key focus in global agricultural research. Maize possesses a rich resource of leaf color mutants, which serve as valuable materials for studying leaf photosynthesis.
View Article and Find Full Text PDFJ Agric Food Chem
September 2025
State Key Laboratory of Green Pesticide, Center for R&D of Fine Chemicals of Guizhou University, Guiyang 550025, P. R. China.
The invasive white-backed planthopper (WBP) poses a severe threat to global rice crop security, and most populations have developed significant resistance to neonicotinoids. Although these species remain sensitive to mesoionic triflumezopyrim (TFM), both neonicotinoids and TFM are hazardous to pollinating insects. Herein, we disclose a series of new spirocompounds designed via isosteric ring replacement of scaffold hopping.
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