Crystallographic and thermodynamic evidence of negative cooperativity of flavin and tryptophan binding in the flavin-dependent halogenases AbeH and BorH.

ABSTRACT: The flavin-dependent halogenase AbeH produces 5-chlorotryptophan in the biosynthetic pathway of the chlorinated bisindole alkaloid BE-54017. We report that in vitro, AbeH (assisted by the flavin reductase AbeF) can chlorinate and brominate tryptophan as well as other indole derivatives and substrates with phenyl and quinoline groups. We solved the X-ray crystal structures of AbeH alone and complexed with FAD, as well as crystal structures of the tryptophan-6-halogenase BorH alone, in complex with 6-chlorotryptophan, and in complex with FAD and tryptophan. Partitioning of FAD and tryptophan into different chains of BorH and failure to incorporate tryptophan into AbeH/FAD crystals suggested that flavin and tryptophan binding are negatively coupled in both proteins. ITC and fluorescenc

SUBMITTER: Ashaduzzaman M 

PROVIDER: S-EPMC10473636 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature