Overproduction and characterization of the first enzyme of a new aldoxime dehydratase family in Bradyrhizobium sp

0491995 - MBÚ 2019 RIV GB eng J - Journal Article
Rädisch, Robert - Chmátal, Martin - Rucká, Lenka - Novotný, Petr - Petrásková, Lucie - Halada, Petr - Kotík, Michael - Pátek, Miroslav - Martínková, Ludmila
Overproduction and characterization of the first enzyme of a new aldoxime dehydratase family in Bradyrhizobium sp.
International Journal of Biological Macromolecules. Roč. 115, AUG 2018 (2018), s. 746-753. ISSN 0141-8130. E-ISSN 1879-0003
R&D Projects: GA MŠMT(CZ) LD15107
Institutional support: RVO:61388971
Keywords : Aldoxime dehydratase * Nitrilase * Bradyrhizobium sp
OECD category: Microbiology
Impact factor: 4.784, year: 2018

Almost 100 genes within the genus Bradyrhizobium are known to potentially encode aldoxime dehydratases (Oxds), but none of the corresponding proteins have been characterized yet. Aldoximes are natural substances involved in plant defense and auxin synthesis, and Oxds are components of enzymatic cascades enabling bacteria to transform, utilize and detoxify them. The aim of this work was to characterize a representative of the highly conserved Oxds in Bradyrhizobium spp. which include both plant symbionts and members of the soil communities. The selected oxd gene from Bradyrhizobium sp. LTSPM299 was expressed in Escherichia coli, and the corresponding gene product (OxdBr1, GenBank: WP_044589203) was obtained as an N-His(6)-tagged protein (monomer, 40.7 kDa) with 30-47% identity to Oxds characterized previously. OxdBrl was most stable at pH ca. 7.0-8.0 and at up to 30 degrees C. As substrates, the enzyme acted on (aryl)aliphatic aldoximes such as E/Z-phenylacetaldoxime, E/Z-2-phenylpropionaldoxime, E/Z-3-phenylpropionaldoxime, E/Z-indole-3-acetaldoxime, E/Z-propionaldoxime, E/Z-butyraldoxime, E/Z-valeraldoxime and E/Z-isovaleraldoxime. Some of the reaction products of OxdBrl are substrates of nitrilases occurring in the same genus. Regions upstream of the oxd gene contained genes encoding a putative aliphatic nitrilase and its transcriptional activator, indicating the participation of OxdBrl in the metabolic route from aldoximes to carboxylic acids.
Permanent Link: http://hdl.handle.net/11104/0285590