196801-10-2Relevant academic research and scientific papers
HheG, a halohydrin dehalogenase with activity on cyclic epoxides
Koopmeiners, Julia,Diederich, Christina,Solarczek, Jennifer,Vo?, Hauke,Mayer, Janine,Blankenfeldt, Wulf,Schallmey, Anett
, p. 6877 - 6886 (2017)
Halohydrin dehalogenases (HHDHs) are of biotechnological interest due to their promiscuous epoxide ring-opening activity with a set of negatively charged nucleophiles, enabling the formation of C-C, C-N, or C-O bonds. The recent discovery of HHDH-specific sequence motifs aided the identification of a large number of halohydrin dehalogenases from public sequence databases, enlarging the biocatalytic toolbox substantially. During the characterization of 17 representatives of these phylogenetically diverse enzymes, one HHDH, namely HheG from Ilumatobacter coccineus, was identified to convert cyclic epoxide substrates. The enzyme exhibits significant activity in the azidolysis of cyclohexene oxide and limonene oxide with turnover numbers of 7.8 and 44 s-1, respectively. As observed for other HHDHs, the cyanide-mediated epoxide ring-opening proceeded with lower rates. Wild-type HheG displays modest enantioselectivity, as the resulting azido- and cyanoalcohols of cyclohexene oxide ring-opening were obtained in 40% enantiomeric excess. These biocatalytic findings were further complemented by the crystal structure of the enzyme refined to 2.3 ?. Analysis of HheG's structure revealed a large open cleft harboring the active site. This is in sharp contrast to other known HHDH structures and aids in explaining the special substrate scope of HheG.
Developing a Biocascade Process: Concurrent Ketone Reduction-Nitrile Hydrolysis of 2-Oxocycloalkanecarbonitriles
Liardo, Elisa,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Rebolledo, Francisca
supporting information, p. 3366 - 3369 (2016/07/26)
A stereoselective bioreduction of 2-oxocycloalkanecarbonitriles was concurrently coupled to a whole cell-catalyzed nitrile hydrolysis in one-pot. The first step, mediated by ketoreductases, involved a dynamic reductive kinetic resolution, which led to 2-hydroxycycloalkanenitriles in very high enantio- and diastereomeric ratios. Then, the simultaneous exposure to nitrile hydratase and amidase from whole cells of Rhodococcus rhodochrous provided the corresponding 2-hydroxycycloalkanecarboxylic acids with excellent overall yield and optical purity for the all-enzymatic cascade.
Cytochrome P450 catalyzed oxidative hydroxylation of achiral organic compounds with simultaneous creation of two chirality centers in a single C-H activation step
Roiban, Gheorghe-Doru,Agudo, Ruben,Reetz, Manfred T.
supporting information, p. 8659 - 8663 (2014/08/18)
Regio- and stereoselective oxidative hydroxylation of achiral or chiral organic compounds mediated by synthetic reagents, catalysts, or enzymes generally leads to the formation of one new chiral center that appears in the respective enantiomeric or diastereomeric alcohols. By contrast, when subjecting appropriate achiral compounds to this type of C-H activation, the simultaneous creation of two chiral centers with a defined relative and absolute configuration may result, provided that control of the regio-, diastereo-, and enantioselectivity is ensured. The present study demonstrates that such control is possible by using wild type or mutant forms of the monooxygenase cytochrome P450 BM3 as catalysts in the oxidative hydroxylation of methylcyclohexane and seven other monosubstituted cyclohexane derivatives.
Dynamic kinetic resolution of 2-oxocycloalkanecarbonitriles: Chemoenzymatic syntheses of optically active cyclic β- and γ-amino alcohols
Dehli, Juan R.,Gotor, Vicente
, p. 6816 - 6819 (2007/10/03)
A series of fungi and yeasts have been tested for the stereoselective bioreduction of 2-oxocycloalkanecar-bonitriles, 1. The yeast Saccharomyces montanus CBS 6772 yielded the corresponding cis-hydroxy nitriles, 2, in >90% ee and de and in high chemical yields. Through simple and efficient procedures, they were transformed into optically active 2-amino and 2-aminomethyl cycloalkanols.
Preparation of the stereoisomers of 2-cyanocycloalkanols by lipase-catalysed acylation
Forro, Eniko,Lundell, Katri,Fueloep, Ferenc,Kanerva, Liisa T.
, p. 3095 - 3099 (2007/10/03)
Enantiopure (1R,2R)-, (1S,2S)-, (1S,2R)- and (1R,2S)-2-cyanocyclopentanol and -cyclohexanol isomers were prepared through the Pseudomonas cepacia lipase-catalysed acetylation of the racemic cis and trans compounds with vinyl acetate in diisopropyl ether.
