Acyl transferase from Mycobacterium smegmatis (MsAcT) is a promising biocatalyst because it catalyzes an acyl transfer reaction in aqueous solution, thereby accepting many primary and secondary alcohols as substrates. MsAcT also exhibits high enantioselectivity for a selected number of secondary alcohols. To increase the applicability of this enzyme for the production of optically active compounds, a detailed understanding of the reaction mechanism and the factors that affect enantioselectivity is essential. Herein, quantum chemical calculations are employed to study the reactions of two secondary alcohols, 1-isopropyl propargyl alcohol and 2-hydroxy propanenitrile, for which the enzyme displays opposite enantiopreference, favoring the S enantiomer in the former case and R enantiomer in the latter. A model of the active site has been designed and for both substrates various binding modes are evaluated and the intermediates and transition states along the reaction path are then located. The calculated energy profiles agree with the experimental observations, and reproduce the selectivity outcome. Through a detailed analysis of the geometries of key transition states, insights into the origins of the enantiopreference are obtained.
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http://dx.doi.org/10.1002/chem.201902351 | DOI Listing |
Nat Commun
December 2024
Laboratory of Aging Research and Cancer Drug Target, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, China.
The immune escape capacities of XBB variants necessitate the authorization of vaccines with these antigens. In this study, we produce three recombinant trimeric proteins from the RBD sequences of Delta, BA.5, and XBB.
View Article and Find Full Text PDFNat Commun
December 2024
Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
The functionalized polycycle with densely contiguous tertiary stereocenters is a formidable challenge in synthesizing the parvistemoline family of Stemona alkaloids. We herein report their catalytic, asymmetric total syntheses in 13-14 steps from commercially available 2-(methoxycarbonyl)-pyrrole, featuring the development and deployment of an Ir/Pd-synergistically-catalyzed allylation of α-non-substituted keto esters with secondary aryl-substituted alcohols, stereodivergently accessible to four stereoisomers. Using chiral Pd-enolate and Ir π-allyl complex under neutral conditions, no epimerization occurs.
View Article and Find Full Text PDFBiomed Res Int
December 2024
Department of Biochemistry & Chemistry, Sylhet Agricultural University, Sylhet, Bangladesh.
Emerging multidrug-resistant (MDR) strains are the main challenges to the progression of new drug discovery. To diminish infectious disease-causing pathogens, new antibiotics are required while the drying pipeline of potent antibiotics is adding to the severity. Plant secondary metabolites or phytochemicals including alkaloids, phenols, flavonoids, and terpenes have successfully demonstrated their inhibitory potential against the drug-resistant pathogens.
View Article and Find Full Text PDFBackground: Hepatocellular carcinoma (HCC) is a major public health concern in Thailand, ranking as the leading cause of cancer-related mortality in Thai people. This study aimed to identify various risk factors for HCC among patients treated at the National Cancer Institute (NCI) in Thailand.
Methods: The retrospective case-control study was conducted using secondary data sources from the Liver Cancer Prevention and Control Research project which was carried out at NCI from 2008 to 2010.
Sci Rep
December 2024
International Institute for Population Sciences, Mumbai, Maharashtra, 400088, India.
The COVID-19 pandemic has not only posed alarming health challenges but also exacerbated the scenarios of intimate partner violence (IPV) against women globally. While global studies indicate a conspicuous increase in IPV during COVID-19 lockdowns; Indian studies exhibit mixed evidence. This ambiguity in world's most populous country underscores a greater need to examine the nexus between exposure to COVID-19 and IPV using a large nationally representative sample of India.
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