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: The sequence homology search using the amino acid sequence coded by ORF1491 revealed significant homology with several multifunctional flavin‐containing monooxygenases, the N‐hydroxylating monooxygenases and BVMO. The presence of two Rossmann folds, as evidenced by two GXGXX(G/A) motifs (Fig. > 3), which is a common sequence among FAD and NAD(P)H‐dependent oxidoreductases, discriminates the enzyme from the mechanistically related flavoprotein hydroxylases (Eppink et al., 1997). Furthermore, the presence of an identified sequence fingerprint (FXGXXXHXXXW(P/D) (Fig. 3) suggests that the protein is a flavin‐containing Baeyer‐Villiger monooxygenase (Fraaije et al., 2002). Indeed a search in the protein sequence database revealed that the closest homologue with known activity is ethionamide‐activating monooxygenase from Mycobacterium tuberculosis, sharing a 49.7% sequence identity and 71.0% sequence similarity.
Affiliation: Department of Life Sciences and Systems Biology, University of Torino, via Accademia Albertina 13, 10123 Torino, Italy.