Anaerobic CO dehydrogenases catalyze the reversible oxidation of CO to CO2 at a complex Ni-, Fe-, and S-containing metal center called cluster C. We report crystal structures of CO dehydrogenase II from Carboxydothermus hydrogenoformans in three different states. In a reduced state, exogenous CO2 supplied in solution is bound and reductively activated by cluster C. In the intermediate structure, CO2 acts as a bridging ligand between Ni and the asymmetrically coordinated Fe, where it completes the square-planar coordination of the Ni ion. It replaces a water/hydroxo ligand bound to the Fe ion in the other two states. The structures define the mechanism of CO oxidation and CO2 reduction at the Ni-Fe site of cluster C.
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http://dx.doi.org/10.1126/science.1148481 | DOI Listing |
Adv Mater
January 2025
Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
The rapid advancement of covalent organic frameworks (COFs) in recent years has firmly established them as a new class of molecularly precise and highly tuneable porous materials. However, compared to other porous materials, such as zeolites and metal-organic frameworks, the successful integration of hierarchical porosity into COFs remains largely unexplored. The challenge lies in identifying appropriate synthetic methods to introduce secondary pores without compromising the intrinsic structural porosity of COFs.
View Article and Find Full Text PDFBMC Plant Biol
January 2025
College of Science, Beijing Forestry University, Beijing, China.
Background: Estimating the CO response of forest trees is of great significance in plant photosynthesis research. CO response measurement is traditionally employed under steady state conditions. With the development of open-path gas exchange systems, the Dynamic Assimilation Technique (DAT), allows measurement under non-steady state conditions.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom.
Mass transfer governs the overall catalytic performance of heterogeneous catalysts considerably; however, this fundamental research has often been ignored. Here, macroporous SiO-supported Pt nanoparticle (Pt/SiO-M) and mesoporous SiO-supported Pt nanoparticle (Pt/SiO-m) catalysts were specifically fabricated by a facile thermal reduction step to engineer the resultant Pt nanoparticles showing similar physiochemical properties while possessing completely different porous microstructures exclusively originating from SiO supports. On this basis, a platform to explore the crucial mass transfer difference affecting catalytic activity is then established by systematically practicing industry-important benzene oxidation measurements.
View Article and Find Full Text PDFSci Rep
January 2025
Florida State University, Tallahassee, FL, 32306-2400, USA.
Sphagnum-dominated bogs are climatically impactful systems that exhibit two puzzling characteristics: CO:CH ratios are greater than those predicted by electron balance models and C decomposition rates are enigmatically slow. We hypothesized that Maillard reactions partially explain both phenomena by increasing apparent CO production via eliminative decarboxylation and sequestering bioavailable nitrogen (N). We tested this hypothesis using incubations of sterilized Maillard reactants, and live and sterilized bog peat.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Key Laboratory of Luminescence Analysis and Molecular Sensing (Ministry of Education), College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China. Electronic address:
Background: Drug enantiomers often display distinguishable or even opposite pharmacological and toxicologic activities. Therefore it is of great necessity to discriminate enantiomers for guaranteeing safetyness and effectiveness of chiral drugs. Facile chiral discrimination has long been a noticeable challenge because of the minimal differences in physicochemical properties of enantiomers.
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