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Xylan, a prominent component of cellulosic biomass, has a high potential for degradation into reducing sugars, and subsequent conversion into bioethanol. This process requires a range of xylanolytic enzymes. Among them, β-xylosidases are crucial, because they hydrolyze more glycosidic bonds than any of the other xylanolytic enzymes. They also enhance the efficiency of the process by degrading xylooligosaccharides, which are potent inhibitors of other hemicellulose-/xylan-converting enzymes. On the other hand, the β-xylosidase itself is also inhibited by monosaccharides that may be generated in high concentrations during the saccharification process. Structurally, β-xylosidases are diverse enzymes with different substrate specificities and enzyme mechanisms. Here, we review the structural diversity and catalytic mechanisms of β-xylosidases, and discuss their inhibition by monosaccharides.
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http://dx.doi.org/10.3390/ijms20225524 | DOI Listing |
Curr Opin Microbiol
September 2025
Cryptosporidiosis Laboratory, The Francis Crick Institute, London, United Kingdom. Electronic address:
The movement of molecules across the membranous barriers of a cell is fundamental to cellular homeostasis in every living organism. This vital process is facilitated through a mechanistically diverse class of proteins, collectively known as membrane transporters. Among these are so-called carrier proteins that can function in passive and active transport mechanisms.
View Article and Find Full Text PDFOrg Lett
September 2025
State Key Laboratory of Natural Product Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
Herein, we report that a novel and efficient bifunctional reagent, benzophenonoxime -(CF) thiocarbonate (BOST), is easily synthesized and successfully applied to the 1, ( ≥ 2)-trifluoromethylthioamination of alkenes under photocatalytic energy transfer conditions. This study not only achieves the radical trifluoromethylthioamination of olefins for the first time but also provides structurally important and diverse SCF-featured amino acid esters and amino nitriles that were previously inaccessible.
View Article and Find Full Text PDFRetina
September 2025
From the Vitreous, Retina, Macula Consultants of New York, New York, NY.
Purpose: To reassess the anatomic basis of optic disc pit maculopathy (OPM) using swept-source optical coherence tomography (SS-OCT) and to characterize the broader structural abnormalities comprising the optic pit complex.
Methods: Sixteen patients with OPM were imaged using a high-resolution SS-OCT system (DREAM OCT). Cross-sectional and volume-rendered scans were analyzed for lamina cribrosa defects, intraneural cavitations, and pathways for fluid entry into or beneath the retina.
J Am Chem Soc
September 2025
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
The direct cross-coupling of unactivated alkyl halides with aryl or heteroaryl partners remains a fundamental challenge in synthetic chemistry due to their inertness and propensity for side reactions. Herein, we report a transition-metal-free electrochemical halogen-atom transfer strategy that enables efficient alkyl radical cross-coupling via convergent paired electrolysis. In this system, anodically generated α-aminoalkyl radicals mediate the activation of alkyl iodides, while aryl/heteroaryl aldehydes or nitriles undergo cathodic reduction to afford persistent ketyl radical anions or aryl radical anions.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States.
Genetic code expansion (GCE) technology has primarily been devoted to the introduction of noncanonical amino acids (ncAAs) into ribosomally synthesized proteins or peptides. Its potential for modifying nonribosomal natural products remains unexplored. In this study, we introduce a novel strategy that integrates GCE with the directed evolution of cyclodipeptide synthase (CDPS) to engineer a new class of CDPSs capable of biosynthesizing cyclodipeptides containing ncAAs.
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