Identification of a novel Baeyer-Villiger monooxygenase from Acinetobacter radioresistens: close relationship to the Mycobacterium tuberculosis prodrug activator EtaA.
Bottom Line: Phylogenetic analysis placed the sequence of this novel BVMO in the same clade of the prodrug activator ethionamide monooxygenase (EtaA) and it bears only a distant relation to the other known class I BVMO proteins.In silico analysis of the 3D model of the S13 BVMO generated by homology modelling also supports the similarities with EtaA by binding ethionamide to the active site.In vitro experiments carried out with the purified enzyme confirm that this novel BVMO is indeed capable of typical Baeyer-Villiger reactions as well as oxidation of the prodrug ethionamide.
Affiliation: Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy.Show MeSH
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Mentions: Following purification of Ar‐BVMO heterologously expressed in Escherichia coli BL21 (DE3) as described in Experimental procedures, its activity was tested with 4‐phenyl‐2‐butanone and the prodrug ethionamide as these compounds are known substrates of Eta A. When incubated with Ar‐BVMO both compounds led to the formation of a product as shown in Fig. 8. Analysis with commercially available standards confirmed that the peak with the retention time of 8.8 min (Fig. 8B) corresponded to the phenethyl acetate, which is the Baeyer‐Villiger product of 4‐phenyl‐2‐butanone oxidation. In the case of ethionamide, spectroscopic analysis of the peak with the retention time of 11.0 min confirmed the presence of ethionamide S‐oxide product (Vannelli et al., 2002). In both cases control experiments preformed in the absence of the enzyme (Fig. 8A and C) resulted in no product being formed.
Affiliation: Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy.