The prodrug activator EtaA from Mycobacterium tuberculosis is a Baeyer-Villiger monooxygenase
| Autor: | Nanne M. Kamerbeek, Dick B. Janssen, Riccardo Fortin, Annelies J. Heidekamp, Marco W. Fraaije |
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| Přispěvatelé: | Groningen Biomolecular Sciences and Biotechnology, Biotechnology, Faculty of Science and Engineering |
| Rok vydání: | 2003 |
| Předmět: |
GENE-CLUSTER
Time Factors Stereochemistry Phenylacetone Amino Acid Motifs Antitubercular Agents Flavin group OXIDATION Biochemistry 4-HYDROXYACETOPHENONE MONOOXYGENASE SEQUENCE Cofactor Catalysis Acetone chemistry.chemical_compound Lactones SUBSTRATE Bacterial Proteins BIOSYNTHESIS Prodrugs Enzyme kinetics Ethionamide Molecular Biology Serum Albumin Phenylacetone monooxygenase biology IDENTIFICATION Dose-Response Relationship Drug Benzylacetone DRUG ETHIONAMIDE Esters Cell Biology Mycobacterium tuberculosis Monooxygenase Prodrug CHEMOTHERAPY Ketones Recombinant Proteins Oxygen Kinetics chemistry Models Chemical Spectrophotometry biology.protein Oxygenases Oxidation-Reduction MYCOLIC ACIDS Protein Binding |
| Zdroj: | The Journal of Biological Chemistry, 279(11), 3354-3360. AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC |
| ISSN: | 0021-9258 |
| Popis: | EtaA is a newly identified FAD-containing monooxygenase that is responsible for activation of several thioamide prodrugs in Mycobacterium tuberculosis. It was found that purified EtaA displays a remarkably low activity with the antitubercular prodrug ethionamide. Hinted by the presence of a Baeyer-Villiger monooxygenase sequence motif in the EtaA sequence, we have been able to identify a large number of novel EtaA substrates. It was discovered that the enzyme converts a wide range of ketones to the corresponding esters or lactones via a Baeyer-Villiger reaction, indicating that EtaA represents a Baeyer-Villiger monooxygenase. With the exception of aromatic ketones (phenylacetone and benzylacetone), long-chain ketones (e.g. 2-hexanone and 2-dodecanone) also are converted. EtaA is also able to catalyze enantioselective sulfoxidation of methyl-p-tolylsulfide. Conversion of all of the identified substrates is relatively slow with typical k(cat) values of around 0.02 s(-1). The best substrate identified so far is phenylacetone (K(m) = 61 microM, k(cat) = 0.017 s(-1)). Redox monitoring of the flavin cofactor during turnover of phenylacetone indicates that a step in the reductive half-reaction is limiting the rate of catalysis. Intriguingly, EtaA activity could be increased by one order of magnitude by adding bovine serum albumin. This reactivity and substrate acceptance-profiling study provides valuable information concerning this newly identified prodrug activator from M. tuberculosis. |
| Databáze: | OpenAIRE |
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