Divorce in the two-component BVMO family: the single oxygenase for enantioselective chemo-enzymatic Baeyer–Villiger oxidations

Abstract

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...

The Isoenzymic Diketocamphane Monooxygenases of Pseudomonas putida ATCC 17453—An Episodic History and Still Mysterious after 60 Years

“…Considered from a different perspective, one possible implication of this and other related previous studies [47,70] is that in the absence of membrane-bound subcellular organelles in the prokaryotic cells of camphor-grown P. putida ATCC 17453, PdR and the various chromosome-coded reductases may, as circumstances dictate, contribute to a 'pool' of unbound FMNH 2 (Figure 14), which is then available as a shared resource to be exploited on an ad hoc basis by the DKCMOs and any other coincidentally present FMNH 2-dependent enzymes. This resonates directly with a speculative suggestion made by Gunsalus nearly 60 years ago [38], and which has been given additional contemporary support by the very recent confirmed ability of reductase-free biomimetic FMNH 2-generating systems to serve as the redox partner to promote efficient 2,5-DKCMO-catalysed lactonization reactions [93]. Ironically, this pageant of events provides a paradigm of the six-decade quest to characterise the isoenzymic DKCMOs of camphor-grown P. putida ATCC 17453.…”

“…That four different identified reductases present in camphor-grown P. putida ATCC 17453 can serve effectively as distal sources of the requisite FMNH 2 for both of the DKCMOs confirms the non-specific nature these redox relationships, as is a characteristic feature of fd-TCMOs [2]. This catholic relationship has been emphasised further by the recent demonstration that biomimetic nicotinamide analogues serving as hydride donors can participate in reductasefree FMNH 2 generating systems able to support the biooxygenating activity of highly purified 2,5-DKCMO [93].…”

Exploring the Temperature Effect on Enantioselectivity of a Baeyer‐Villiger Biooxidation by the 2,5‐DKCMO Module: The SLM Approach

“…The prediction of the mechanistic details appears to be particularly challenging for the present reaction, and a simple mechanism, as is required for most of the kinetic models, cannot be proposed. A closer look at the time curve of each compound and its enantiomers (Figure S2) revealed a more complex behaviour than a classical simple kinetic resolution as previously described [11] . Thus, at lower temperatures, two reaction phases were visible.…”

“…In this work, the FMN cofactor is chemically reduced by a direct hydride transfer via the artificial hydride donor AmNAH (Scheme 2). [11] The fully reduced flavin hydroquinone (FMNH 2 ), which is the electron mediator for the 2,5‐DKCMO, diffuses into the active site of the enzyme, where the reactive flavin C4a‐hydroperoxide is formed in the presence of molecular oxygen.…”

Asymmetric azidohydroxylation of styrene derivatives mediated by a biomimetic styrene monooxygenase enzymatic cascade

“…[24][25][26][27][28][29] In particular, 1benzyl-1,4-dihydronicotinamide (BNAH) was shown to be effective and simple to use as a reductant with StyA 16,30 and other two-component flavoprotein monooxygenases such as halogenases, 31 a bacterial luciferase, 32 and an FMN-dependent type II Baeyer-Villiger monooxygenase. 33 BNAH thus circumvents the use of two enzymes (StyB, dehydrogenase) and NADH, for using oxygenase StyA in biocatalytic reactions (Figure 1B). Previous enzymatic cascades involving two-component SMOs have led to the synthesis of amino acids and other valuable chiral compounds.…”