43119-28-4Relevant academic research and scientific papers
Divorce in the two-component BVMO family: The single oxygenase for enantioselective chemo-enzymatic Baeyer-Villiger oxidations
R?llig, Robert,Paul, Caroline E.,Claeys-Bruno, Magalie,Duquesne, Katia,Kara, Selin,Alphand, Véronique
supporting information, p. 3441 - 3450 (2021/05/03)
Two-component flavoprotein monooxygenases consist of a reductase and an oxygenase enzyme. The proof of functionality of the latter without its counterpart as well as the mechanism of flavin transfer remains unanswered beyond doubt. To tackle this question, we utilized a reductase-free reaction system applying purified 2,5-diketocamphane-monooxygenase I (2,5-DKCMO), a FMN-dependent type II Baeyer-Villiger monooxygenase, and synthetic nicotinamide analogues (NCBs) as dihydropyridine derivatives for FMN reduction. This system demonstrated the stand-alone quality of the oxygenase, as well as the mechanism of FMNH2transport by free diffusion. The efficiency of this reductase-free system strongly relies on the balance of FMN reduction and enzymatic (re)oxidation, since reduced FMN in solution causes undesired side reactions, such as hydrogen peroxide formation. Design of experiments allowed us to (i) investigate the effect of various reaction parameters, underlining the importance to balance the FMN/FMNH2cycle, (ii) optimize the reaction system for the enzymatic Baeyer-Villiger oxidation of rac-bicyclo[3.2.0]hept-2-en-6-one,rac-camphor, andrac-norcamphor. Finally, this study not only demonstrates the reductase-independence of 2,5-DKCMO, but also revisits the terminology of two-component flavoprotein monooxygenases for this specific case.
Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential
Bianchi, Dario A.,Carabajal, María Ayelén,Ceccoli, Romina D.,Rial, Daniela V.
, (2020/03/19)
Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.
Controlling the Regioselectivity of Baeyer–Villiger Monooxygenases by Mutation of Active-Site Residues
Balke, Kathleen,B?umgen, Marcus,Bornscheuer, Uwe T.
, p. 1627 - 1638 (2017/08/26)
Baeyer–Villiger monooxygenase (BVMO)-mediated regiodivergent conversions of asymmetric ketones can lead to the formation of “normal” or “abnormal” lactones. In a previous study, we were able to change the regioselectivity of a BVMO by mutation of the active-site residues to smaller amino acids, which thus created more space. In this study, we demonstrate that this method can also be used for other BVMO/substrate combinations. We investigated the regioselectivity of 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-CoA monooxygenase from Pseudomonas putida (OTEMO) for cis-bicyclo[3.2.0]hept-2-en-6-one (1) and trans-dihydrocarvone (2), and we were able to switch the regioselectivity of this enzyme for one of the substrate enantiomers. The OTEMO wild-type enzyme converted (?)-1 into an equal (50:50) mixture of the normal and abnormal products. The F255A/F443V variant produced 90 % of the normal product, whereas the W501V variant formed up to 98 % of the abnormal product. OTEMO F255A exclusively produced the normal lactone from (+)-2, whereas the wild-type enzyme was selective for the production of the abnormal product. The positions of these amino acids were equivalent to those mutated in the cyclohexanone monooxygenases from Arthrobacter sp. and Acinetobacter sp. (CHMOArthro and CHMOAcineto) to switch their regioselectivity towards (+)-2, which suggests that there are hot spots in the active site of BVMOs that can be targeted with the aim to change the regioselectivity.
Characterization and Crystal Structure of a Robust Cyclohexanone Monooxygenase
Romero, Elvira,Castellanos, J. Rubén Gómez,Mattevi, Andrea,Fraaije, Marco W.
supporting information, p. 15852 - 15855 (2016/12/16)
Cyclohexanone monooxygenase (CHMO) is a promising biocatalyst for industrial reactions owing to its broad substrate spectrum and excellent regio-, chemo-, and enantioselectivity. However, the low stability of many Baeyer–Villiger monooxygenases is an obstacle for their exploitation in industry. Characterization and crystal structure determination of a robust CHMO from Thermocrispum municipale is reported. The enzyme efficiently converts a variety of aliphatic, aromatic, and cyclic ketones, as well as prochiral sulfides. A compact substrate-binding cavity explains its preference for small rather than bulky substrates. Small-scale conversions with either purified enzyme or whole cells demonstrated the remarkable properties of this newly discovered CHMO. The exceptional solvent tolerance and thermostability make the enzyme very attractive for biotechnology.
E. coli cells expressing the Baeyer-Villiger monooxygenase 'MO14' (ro03437) from Rhodococcus jostii RHA1 catalyse the gram-scale resolution of a bicyclic ketone in a fermentor
Summers, Benjamin D.,Omar, Muhiadin,Ronson, Thomas O.,Cartwright, Jared,Lloyd, Michael,Grogan, Gideon
, p. 1897 - 1903 (2015/02/19)
The Baeyer-Villiger monooxygenase (BVMO) 'MO14' from Rhodococcus jostii RHA1, is an enantioselective BVMO that catalyses the resolution of the model ketone substrate bicyclo[3.2.0]hept-2-en-6-one to the (1S,5R)-2-oxa lactone and the residual (1S,5R)-substrate enantiomer. This regio-plus enantioselective behaviour is highly unusual for BVMOs, which often perform enantiodivergent biotransformations of this substrate. The scaleability of the transformation was investigated using fermentor-based experiments, in which variables including gene codon optimisation, temperature and substrate concentration were investigated. E. coli cells expressing MO14 catalysed the resolution of bicyclo[3.2.0]hept-2-en-6-one to yield (1S,5R)-2-oxa lactone of >99% ee and (1S,5R)-ketone of 96% ee after 14 h at a temperature of 16 °C and a substrate concentration of 0.5 g L-1 (4.5 mM). MO14 is thus a promising biocatalyst for the production of enantio-enriched ketones and lactones derived from the [3.2.0] platform.
Jatrophane diterpenes: Preparation of the western fragment of pl-3
Lentsch, Christoph,Fuerst, Rita,Mulzer, Johann,Rinner, Uwe
, p. 919 - 923 (2014/03/21)
Jatrophane diterpenes are structurally intriguing natural products with promising biological properties. Herein, the synthesis of the western fragment of the Euphorbiaceae constituent Pl-3 starting from (1R,5S)-bicyclo[3.2.0]hept- 2-en-6-one is described. Key steps in the sequence include a Baeyer-Villiger oxidation, an iodolactonization reaction, and the installation of the northern side chain through the addition of a lithiated vinyl bromide. The overall efficiency of the route is increased by taking advantage of latent symmetry. The synthesis of the western fragment of Pl-3 is developed by taking advantage of the latent symmetry in an intermediate; both enantiomers are thus converted into the desired substrate. Key steps of the synthesis include a Baeyer-Villiger oxidation, an iodolactonization reaction, and the addition of a vinyllithium species to the completed cyclopentane moiety of the natural product.
Type II flavin-containing monooxygenases: A new class of biocatalysts that harbors baeyer-villiger monooxygenases with a relaxed coenzyme specificity
Riebel, Anette,Fink, Michael J.,Mihovilovic, Marko D.,Fraaije, Marco W.
, p. 1112 - 1117 (2014/05/06)
Within a newly identified set of flavin-containing monooxygenases (FMOs) from Rhodococcus jostii RHA1, we have identified three monooxygenases (FMO-E, FMO-F, and FMO-G) that are effective in catalyzing Baeyer-Villiger oxidations. These type II FMOs display relaxed coenzyme specificity by accepting both NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) and NADH (reduced form of nicotinamide adenine dinucleotide), as a coenzyme, which is a novel and attractive feature among biocatalysts capable of conducting Baeyer-Villiger oxidations. We purified FMO-E and determined that the Michaelis constants for both coenzymes were in the micromolar range, whereas the activity was highest for NADH. By using the stopped-flow technique, formation of a peroxyflavin-enzyme intermediate was observed, which indicated that type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio- and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially norcamphor), and exhibited excellent and unique regio- and enantioselectivities. Sequence analysis revealed that type II FMOs that act as Baeyer-Villiger monooxygenases contain a unique N-terminal domain. Sequence conservation in this protein domain can be used to identify new NADH-dependent Baeyer-Villiger monooxygenases, which would facilitate future biocatalyst discovery efforts. New kid on the block: Members of a newly recognized group of sequence-related flavin-containing monooxygenases can perform Baeyer-Villiger oxidations. Their coenzyme indifference and unique specificity make them attractive biocatalysts.
Discovery of Baeyer-Villiger monooxygenases from photosynthetic eukaryotes
Beneventi, Elisa,Niero, Mattia,Motterle, Riccardo,Fraaije, Marco,Bergantino, Elisabetta
, p. 145 - 154 (2013/12/04)
Baeyer-Villiger monooxygenases are attractive "green" catalysts able to produce chiral esters or lactones starting from ketones. They can act as natural equivalents of peroxyacids that are the catalysts classically used in the organic synthesis reactions, consisting in the cleavage of CC bonds with the concomitant insertion of an oxygen atom. In this study, two type I BVMOs have been identified for the first time in photosynthetic eukaryotic organisms, the red alga Cyanidioschyzon merolae (Cm) and the moss Physcomitrella patens (Pp). A biocatalytic characterization of these newly discovered enzymes, expressed in recombinant forms, was carried out. Both enzymes could be purified as holo enzymes containing a FAD cofactor. Their thermostability was investigated and revealed that the Cm-BVMO is the most thermostable type I BVMO with an apparent melting temperature of 56 C. Substrate profiling revealed that both eukaryotic BVMOs accept a wide range of ketones which include aromatic, aliphatic, aryl aliphatic and bicyclic ketones. In particular, linear aliphatic ketones (C9 and C12), carrying the keto functionality in different positions, resulted to be the best substrates in steady state kinetic analyses. In order to restore the BVMO-typifying sequence motif in the Pp-BVMO, a mutant was prepared (Y160H). Intriguingly, this mutation resulted in higher activities on most tested substrates. The recombinant enzymes displayed kcat values in the 0.1-0.2 s-1 range, which is relatively low when compared with other known type I BVMOs. This may hint to a role in secondary metabolism in these photosynthetic organisms, though their exact function remains to be established.
A Flavoprotein Monooxygenase that Catalyses a Baeyer-Villiger Reaction and Thioether Oxidation Using NADH as the Nicotinamide Cofactor
Jensen, Chantel N.,Cartwright, Jared,Ward, Jonathan,Hart, Sam,Turkenburg, Johan P.,Ali, Sohail T.,Allen, Michael J.,Grogan, Gideon
experimental part, p. 872 - 878 (2012/07/27)
A gene from the marine bacterium Stenotrophomonas maltophilia encodes a 38.6 kDa FAD-containing flavoprotein (Uniprot B2FLR2) named S. maltophilia flavin-containing monooxygenase (SMFMO), which catalyses the oxidation of thioethers and also the regioselective Baeyer-Villiger oxidation of the model substrate bicyclo[3.2.0]hept-2-en-6-one. The enzyme was unusual in its ability to employ either NADH or NADPH as nicotinamide cofactor. The KM and kcat values for NADH were 23.7±9.1 μM and 0.029 s-1 and 27.3±5.3 μM and 0.022 s-1 for NADPH. However, kcat/KM value for the ketone substrate in the presence of 100 μM cofactor was 17 times greater for NADH than for NADPH. SMFMO catalysed the quantitative conversion of 5 mM ketone in the presence of substoichiometric concentrations of NADH with the formate dehydrogenase cofactor recycling system, to give the 2-oxa and 3-oxa lactone products of Baeyer-Villiger reaction in a ratio of 5:1, albeit with poor enantioselectivity. The conversion with NADPH was 15%. SMFMO also catalysed the NADH-dependent transformation of prochiral aromatic thioethers, giving in the best case, 80% ee for the transformation of p-chlorophenyl methyl sulfide to its R enantiomer. The structure of SMFMO reveals that the relaxation in cofactor specificity appears to be accomplished by the substitution of an arginine residue, responsible for recognition of the 2′-phosphate on the NADPH ribose in related NADPH-dependent FMOs, with a glutamine residue in SMFMO. SMFMO is thus representative of a separate class of single-component, flavoprotein monooxygenases that catalyse NADH-dependent oxidations from which possible sequences and strategies for developing NADH-dependent biocatalysts for asymmetric oxygenation reactions might be identified.
Asymmetric baeyer-villiger oxidation of 2,3- and 2,3,4-substituted cyclobutanones catalyzed by chiral phosphoric acids with aqueous H 2O2 as the oxidant
Xu, Senmiao,Wang, Zheng,Zhang, Xumu,Ding, Kuiling
supporting information; experimental part, p. 110 - 116 (2011/03/21)
Catalytic asymmetric Baeyer-Villiger (B-V) oxidation of 2,3,4-trisubstituted cyclobutanone (4) has been realized by the catalysis of a 1,1′-bi-2-naphthol (BINOL)-derived chiral phosphoric acid (1j), which contains bulky 2,4,6-triisopropyl phenyl groups at the 3,3′-positions of the BINOL backbone, using 30% aqueous H2O2 as the oxidant, affording the corresponding Iγ-lactone (5) in 99% yield with 95% ee. In a divergent kinetic resolution of racemic 2,3-disubstituted bicyclic cyclobutanones (6) through asymmetric B-V oxidation, the chiral phosphoric acid 1p demonstrated excellent catalytic performance, giving a range of regioisomeric chiral lactones in a normal lactone (nl)/abnormal lactone (al) ratio of up to 2.1:1, with up to 99% ee in the al product. It was found that fine tuning of the stereoelectronic properties of the backbone in chiral phosphoric acids is critically important for attaining high levels of enantioselectivity in the catalysis of B-V reactions of different type of cyclobutanones. The present work has provided a convenient approach to the synthesis of a variety of optically active chiral Iγ-lactones. Asymmetric Baeyer-Villiger oxidation of tricyclic cyclobutaone and a variety of racemic bicyclic cyclobutanone derivatives has been realized by the catalysis of 1,1′-bi-2-naphthol (BINOL)-derived chiral phosphoric acid with high yields and excellent enantioselectivities using 30% aqueous H2O2 as the oxidant.
