Substitution of active-site Tyr-51 by Ala (Y51A) disrupted the activity of Candida tenuis xylose reductase by six orders of magnitude. External bromide brought about unidirectional rate enhancement ( approximately 2x10(3)-fold at 300mM) for NAD(+)-dependent xylitol oxidation by Y51A. Activity of the wild-type reductase was dependent on a single ionizable protein group exhibiting a pK of 9.2+/-0.1 and 7.3+/-0.3 in the holo-enzyme bound with NADH and NAD(+), respectively. This group which had to be protonated for xylose reduction and unprotonated for xylitol oxidation was eliminated in Y51A, consistent with a catalytic acid-base function of Tyr-51. Bromide may complement the xylitol dehydrogenase activity of Y51A by partly restoring the original hydrogen bond between the reactive alcohol and the phenolate of Tyr-51.
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http://dx.doi.org/10.1016/j.febslet.2008.11.003 | DOI Listing |
Biomolecules
November 2024
Department of Organic Chemistry, Kaunas University of Technology, Radvilėnų pl. 19, 50254 Kaunas, Lithuania.
A series of target 4-substituted-5-(2-(pyridine-2-ylamino)ethyl)-2,4-dihydro-3-1,2,4-triazole-3-thiones and their chloro analogs - were synthesized in a reaction of the selected aldehydes with the corresponding 4-amino-1,2,4-triazole-3-thiones and , which were obtained from 3-(pyridin-2-ylamino)propanoic acid () or 3-((5-chloropyridin-2-yl)amino)propanoic acid (), respectively, with thioacetohydrazide. The antibacterial and antifungal activities of the synthesized hydrazones were screened against the bacteria , , and and the fungi and by agar diffusion and serial dilution methods. 4-Amino-5-(2-((5-chloropyridin-2-yl)amino)ethyl)-2,4-dihydro-3-1,2,4-triazole-3-thione () and 4-(benzylideneamino)-5-(2-(pyridin-2-ylamino)ethyl)-2,4-dihydro-3-1,2,4-triazole-3-thione () were identified as exceptionally active (MIC 0.
View Article and Find Full Text PDFMicrobiol Resour Announc
June 2023
Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
Foods
October 2022
Department of Food Hygiene Technology and Safety, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, 041 81 Košice, Slovakia.
Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.
View Article and Find Full Text PDFAntibiotics (Basel)
January 2022
Department of Biosciences, COMSATS University Islamabad, Islamabad 45600, Pakistan.
Thymoquinone (2-methyl-5-propan-2-ylcyclohexa-2,5-diene-1,4-dione; TQ), a principal bioactive phytoconstituent of essential oil, has been reported to have high antimicrobial potential. Thus, the current study evaluated TQ's antimicrobial potential against a range of selected human pathogens using in vitro assays, including time-kill kinetics and anti-biofilm activity. In silico molecular docking of TQ against several antimicrobial target proteins and a detailed intermolecular interaction analysis was performed, including binding energies and docking feasibility.
View Article and Find Full Text PDFBMC Biotechnol
October 2021
Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, 8010, Graz, Austria.
Background: Published biocatalytic routes for accessing enantiopure 2-phenylpropanol using oxidoreductases afforded maximal product titers of only 80 mM. Enzyme deactivation was identified as the major limitation and was attributed to adduct formation of the aldehyde substrate with amino acid residues of the reductase.
Results: A single point mutant of Candida tenuis xylose reductase (CtXR D51A) with very high catalytic efficiency (43·10 s M) for (S)-2-phenylpropanal was found.
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