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Ultraviolet (UV) irradiation of DNA causes genotoxic photolesions, such as carcinogenic pyrimidine(6-4)pyrimidone photoproducts ((6-4)PPs). In many organisms, (6-4)PPs are repaired by (6-4) photolyases, which contain a flavin chromophore and use blue light energy to initiate the catalytic reaction. Although (6-4)PP repair has been shown to require the input of two successive photons, details of the mechanism remain elusive. Here, we applied recently developed time-resolved UV and infrared (IR) spectroscopic techniques to capture a key intermediate that awaits the second photon in the repair reaction of Xenopus laevis (6-4) photolyase. The results indicate that the intermediate is formed within 500 μs following the initial absorption of a photon and contains a four-membered oxetane ring that bridges two adjacent pyrimidine bases. These findings shed light on the molecular basis of DNA repair involving two-photon activation.
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http://dx.doi.org/10.1038/s42004-025-01625-9 | DOI Listing |
Mol Divers
September 2025
Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004, 61413, Abha, Saudi Arabia.
The catalytic asymmetric Mannich reaction is a multicomponent reaction which affords β-amino carbonyl compounds by utilizing an aldehyde, a primary or secondary amine/ammonia, and a ketone. β-amino carbonyl scaffolds are crucial intermediates for the synthesis of naturally occurring bioactive compounds and their derivatives. The synthesized natural compounds exhibit a broad spectrum of biological activities including anti-fungal, anti-cancer, anti-bacterial, anti-HIV, anti-oxidant, and anti-inflammatory activities.
View Article and Find Full Text PDFEnviron Sci Technol
September 2025
Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China.
Rapidly expanding nascent ecosystems at glacier forefields under climate warming dramatically enhance the terrestrial carbon (C) sink. Microbial C fixation and degradation, closely implicated in nitrogen (N) transformation and plant-soil-microbe interactions, significantly regulate soil C accumulation. However, how shifts in microbial functional potential impact soil C sequestration during vegetation succession remains unclear.
View Article and Find Full Text PDFOrg Lett
September 2025
National Key Laboratory of Advanced Drug Delivery and Release Systems, School of Pharmaceutical Sciences & Institute of Materia Medica, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250117, P. R. China.
A method for the conversion of isoxazoles into thiazoles by skeleton rearrangement has been achieved by an ammonium iodide-catalyzed cycloaddition protocol under mild conditions with a broad substrate scope and good functional group tolerance. Most appealingly, the reaction can proceed smoothly without the addition of any transition metal catalyst. Detailed mechanistic studies, including control experiments and key reaction intermediate characterization, reveal an intermolecular [3+2] cycloaddition reaction pathway.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) State Key Laboratory of Advanced Chemical Power Sources, College of Chemistry, Nankai University, Tianjin 300071, China.
Developing cost-effective spinel oxide catalysts with both high oxygen evolution reaction (OER) activity and stability is crucial for advancing sustainable clean energy conversion. However, practical applications are often hindered by the activity limitations inherent in the adsorbate evolution mechanism (AEM) and the stability limitations associated with the lattice oxygen mechanism (LOM). Herein, we demonstrate structural changes induced by phase transformation in CoMn spinel oxides, which yield more active octahedral sites with shortened intersite distance.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Computational Inorganic Chemistry Group, Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana 502284, India.
Over the past few years, alkali and alkaline earth metals have emerged as alternative catalysts to transition metal organometallics to catalyze the hydroboration of unsaturated compounds. A highly selective and cost-effective lithium-catalyzed method for the synthesis of an organoborane has been established based on the addition of a B-H bond to an unsaturated bond (polarized or unpolarized) using pinacolborane (HBPin). In the present work, the neosilyllithium-catalyzed hydroboration of nitriles, aldehydes, and esters has been investigated using high-level DLPNO-CCSD(T) calculations to unravel the mechanistic pathways and substrate-dependent reactivity.
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