Reaction: 2 3-(7-chloroindol-3-yl)-2-iminopropanoate + H2O2 = dichlorochromopyrrolate + NH3 + 2 H2O
For diagram of reaction click here.
Glossary: dichlorochromopyrrolate = 3,4-bis(7-chloro-1H-indol-3-yl)-1H-pyrrole-2,5-dicarboxylate
Other name(s): RebD; chromopyrrolic acid synthase; chromopyrrolate synthase
Systematic name: 3-(7-chloroindol-3-yl)-2-iminopropanoate ammonia-lyase (dichlorochromopyrrolate-forming)
Comments: This enzyme catalyses a step in the biosynthesis of rebeccamycin, an indolocarbazole alkaloid produced by the bacterium Lechevalieria aerocolonigenes. The enzyme is a dimeric heme-protein oxidase that catalyses the oxidative dimerization of two L-tryptophan-derived molecules to form dichlorochromopyrrolic acid, the precursor for the fused six-ring indolocarbazole scaffold of rebeccamycin [1]. Contains one molecule of heme b per monomer, as well as non-heme iron that is not part of an iron-sulfur center [2]. In vivo the enzyme uses hydrogen peroxide, formed by the enzyme upstream in the biosynthetic pathway (EC 1.4.3.23, 7-chloro-L-tryptophan oxidase) as the electron acceptor. However, the enzyme is also able to catalyse the reaction using molecular oxygen [3].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Nishizawa, T., Gruschow, S., Jayamaha, D.H., Nishizawa-Harada, C. and Sherman, D.H. Enzymatic assembly of the bis-indole core of rebeccamycin. J. Am. Chem. Soc. 128 (2006) 724-725. [PMID: 16417354]
2. Howard-Jones, A.R. and Walsh, C.T. Enzymatic generation of the chromopyrrolic acid scaffold of rebeccamycin by the tandem action of RebO and RebD. Biochemistry 44 (2005) 15652-15663. [PMID: 16313168]
3. Spolitak, T. and Ballou, D.P. Evidence for catalytic intermediates involved in generating the chromopyrrolic acid scaffold of rebeccamycin by RebO and RebD. Arch. Biochem. Biophys. 573 (2015) 111-119. [PMID: 25837855]