32999-55-6Relevant articles and documents
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Kotake et al.
, p. 5085 (1950)
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Characterization of 2-Oxindole Forming Heme Enzyme MarE, Expanding the Functional Diversity of the Tryptophan Dioxygenase Superfamily
Zhang, Yuyang,Zou, Yi,Brock, Nelson L.,Huang, Tingting,Lan, Yingxia,Wang, Xiaozheng,Deng, Zixin,Tang, Yi,Lin, Shuangjun
, p. 11887 - 11894 (2017/09/07)
3-Substituted 2-oxindoles are important structural motifs found in many biologically active natural products and pharmaceutical lead compounds. Here, we report an enzymatic formation of the 3-substituted 2-oxindoles catalyzed by MarE in the maremycin biosynthetic pathway in Streptomyces sp. B9173. MarE is a homologue of FeII/heme-dependent tryptophan 2,3-dioxygenases (TDOs). Typical TDOs usually catalyze the insertion of two oxygen atoms from O2 into an indole ring to generate N-formylkynurenine (NFK)-like products. In contrast, MarE catalyzes the insertion of a single oxygen atom from O2 into an indole ring, to probably generate an epoxyindole intermediate that undergoes an unprecedented 2,3-hydride migration to form 2-oxindole structure. MarE shows substrate robustness to catalyze the conversion of a series of 3-substituted indoles into their corresponding 3-substituted 2-oxindoles. Although containing most key amino acid residues conserved in well-known TDO homologues, MarE falls into a separate new subgroup in the phylogenetic tree. The characterization of MarE and its homologue enriches the functional diversities of TDO superfamily and provides a new strategy for discovering novel natural products containing 3-substituted 2-oxindole pharmacophores by genome mining.
Mass spectrometric analysis of oxidized tryptophan
Van de Weert, Marco,Lagerwerf, Fija M.,Haverkamp, Johan,Heerma, Wigger
, p. 884 - 891 (2007/10/03)
Oxindolylalanine and oxindolylalanine-containing peptides were prepared by treatment of tryptophan and tryptophan-containing peptides with mixtures of dimethyl sulfoxide and hydrochloric acid in acetic acid (DMSO-HCl-HAc). The reaction between tryptophan and DMSO-HCl-HAc was monitored by fast atom bombardment mass spectrometry (FAB-MS) and the proposed chlorotryptophan intermediate in the reaction was observed. Almost complete conversion of tryptophan to oxindolylalanine was obtained in reaction mixtures containing 3.75 M HCl when the reaction was performed in an open tube. A higher HCl concentration (5.5 M) and a closed reaction tube promoted the formation of by-products, such as dioxindolylalanine and 3-chlorooxindolylalanine. Extensive hydrolysis C-terminal of tryptophan was observed when tryptophan-containing peptides were treated with DMSO-HCl-HAc containing 5.5 M HCl, during which the tryptophan residue was modified to dioxindolylalanine lactone. Hydrolysis was not observed in mixtures containing 3.75 M HCl. The presence of oxindolylalanine in peptides could be demonstrated by characteristic peaks in FAB collision-induced dissociation tandem mass spectra.
