Indolyl-3-acetaldoxime dehydratase from the phytopathogenic fungus Sclerotinia sclerotiorum: Purification, characterization, and substrate specificity

• Published in: Phytochemistry (Oxford) Vol. 71; no. 17; pp. 1952 - 1962
• Main Authors: Pedras, M. Soledade C., Minic, Zoran, Thongbam, Premila D., Bhaskar, Vangala, Montaut, Sabine
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.12.2010; Elsevier
• Subjects: Aldoxime dehydratase; amino acid sequences; anaerobic conditions; Ascomycota - enzymology; Bacillus; Bacillus (bacteria); Biochemistry & Molecular Biology; Biological and medical sciences; Botryotinia fuckeliana; Brassicaceae; Catalysis; Chemical constitution; Crucifer; Fundamental and applied biological sciences. Psychology; Gibberella zeae; Indoles - chemistry; Indoles - metabolism; Indolyl-3-acetaldoxime; Life Sciences & Biomedicine; Lyases - metabolism; Molecular Structure; molecular weight; Phenylacetaldoxime; Phytoalexin; Phytoanticipin; plant pathogenic fungi; Plant physiology and development; Plant Sciences; Science & Technology; Sclerotinia fuckeliana; Sclerotinia sclerotiorum; Stereoisomerism; Substrate Specificity; Aldoxime dehydratase; Phenylacetaldoxime; Phytoalexin; Crucifer; Sclerotinia sclerotiorum; Brassicaceae; Indolyl-3-acetaldoxime; Phytoanticipin; 3-INDOLEACETALDOXIME; CONVERSION; INDOLEACETALDOXIME HYDRO-LYASE; NITRILE HYDRATASE; INDOLE-3-ACETALDOXIME; TRIPLE BOND SYNTHESIS; METABOLISM; PHYTOALEXINS; Ascomycota; Purification; Enzyme; Chemical structure; Lyases; Fungi; Characterization; Cruciferae; Dicotyledones; Substrate specificity; Angiospermae; Plant origin; Dehydratase; Spermatophyta; Carbon-oxygen lyases; Hydro-lyases
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2010.10.002

Indolyl-3-acetaldoxime dehydratase was identified as the protein SS1G_01653 from Sclerotinia sclerotiorum with the molecular mass of 44 kDa. The purification and characterization of indolyl-3-acetaldoxime dehydratase produced by the plant fungal pathogen Sclerotinia sclerotiorum is described. The substrate specificity indicates that it is an indolyl-3-acetaldoxime dehydratase (IAD, EC 4.99.1.6), which catalyzes transformation of indolyl-3-acetaldoxime to indolyl-3-acetonitrile. The enzyme showed Michaelis–Menten kinetics and had an apparent molecular mass of 44 kDa. The amino acid sequence of IAD, determined using LC–ESI-MS/MS, identified it as the protein SS1G_01653 from S. sclerotiorum. IADSs was highly homologous (84% amino acid identity) to the hypothetical protein BC1G_14775 from Botryotinia fuckeliana B05.10. In addition, similarity to the phenylacetaldoxime dehydratases from Gibberella zeae (33% amino acid identity) and Bacillus sp. (20% amino acid identity) was noted. The specific activity of IADSs increased about 17-fold upon addition of Na 2S 2O 4 under anaerobic conditions, but in the absence of Na 2S 2O 4 no significant change was observed, whether aerobic or anaerobic conditions were used. As with other aldoxime dehydratases isolated from microbes, the role of IADSs in fungal plant pathogens is not clear, but given its substrate specificity, it appears unlikely that IADSs is a general xenobiotic detoxifying enzyme.