Using directed evolution, a variant N-acetyl amino acid racemase (NAAAR G291D/F323Y) has been developed with up to 6-fold higher activity than the wild-type on a range of N-acetylated amino acids. The variant has been coupled with an enantiospecific acylase to give a preparative scale dynamic kinetic resolution which allows 98% conversion of N-acetyl-DL-allylglycine into D-allylglycine in 18 h at high substrate concentrations (50 g L(-1)). This is the first example of NAAAR operating under conditions which would allow it to be successfully used on an industrial scale for the production of enantiomerically pure α-amino acids. X-ray crystal analysis of the improved NAAAR variant allowed a comparison with the wild-type enzyme. We postulate that a network of novel interactions that result from the introduction of the two side chains is the source of improved catalytic performance.
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http://dx.doi.org/10.1021/ja305438y | DOI Listing |
Nanoscale
January 2025
CBMN, CNRS, UMR 5248, University of Bordeaux, 33600 Pessac, France.
Cast films of racemic helicene derivatives adsorbed onto the surface of nanometric silica helices with controlled handedness exhibited distinct CD signals, whereas no CD signal was observed in the absence of silica nanohelices. These CD signals originate from the helical supramolecular assemblies formed by the racemic mixture of helicenes, with no evidence of enantiospecific adsorption. Interestingly, when enantiomerically pure forms of these helicenes were drop-cast onto the silica helices, different CD spectra were observed depending on the combination of the helicenes' handedness with that of the silica nanohelices.
View Article and Find Full Text PDFChem Asian J
December 2024
Govt. Degree College for Men, Srikakulam, Department of Chemistry, Srikakulam, 532001, Srikakulam, INDIA.
The production of enantiomerically pure compounds remains a vital and valuable objective in modern organic chemistry due to their broad applications in fields such as biosensing, optics, electronics, photonics, catalysis, nanotechnology, and drug or DNA delivery. Optically pure α-hydroxy ketones, in particular, are key structural components in many drugs and natural products with significant biological activity. Among these, benzoin type α-hydroxy ketones, which possess two adjacent functional groups, a carbonyl and a hydroxy group, are especially important.
View Article and Find Full Text PDFCryst Growth Des
December 2024
Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States.
Organometallic antimony(V) complexes were prepared as model compounds to better understand the interactions of chiral chelating diols with this metalloid. These complexes feature three aryl groups (-xylyl or -tolyl) and a bidentate -2,3-butanediolate. The -xylyl and -tolyl complexes of either enantiomerically pure 2,3-butanediolate or 2,3-butanediolate (compounds -) crystallized in Sohncke space groups, as expected.
View Article and Find Full Text PDFArch Biochem Biophys
December 2024
Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100, Pavia, Italy. Electronic address:
Bacterial monoamine oxidases (MAOs) are FAD-dependent proteins catalyzing a relevant reaction for many industrial biocatalytic applications, ranging from production of enantiomerically pure building blocks for pharmaceutical synthesis to biosensors for monitoring food and beverage quality. The thermostable MAO enzyme from Thermoanaerobacterales bacterium (MAO) is about 36 % identical to both putrescine oxidase and human MAOs and can be efficiently produced in Escherichia coli. MAO preferentially acts on n-alkyl monoamines but shows detectable activity also on polyamines and aromatic monoamines.
View Article and Find Full Text PDFCommun Chem
December 2024
Department of Chemistry, University of Zurich, Zurich, Switzerland.
Chirality plays a critical role in the biochemistry of life and often only one enantiomeric series is observed (homochirality). Only a few natural products have been obtained as racemates, e.g.
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