Unusual substrate and halide versatility of phenolic halogenase PltM

Mechanistic insight into halide oxidation by non-heme iron complexes. Haloperoxidase versus halogenase activity.

This work presents the first detailed study on mechanistic aspects of halide oxidation by non-heme iron complexes. We show that while iron(III)-hydroperoxo complexes oxidise halides via oxygen atom transfer, the corresponding iron(IV)-oxo complex reacts via electron transfer.

The structural basis for substrate versatility of chloramphenicol acetyltransferase CATI.

Novel antibiotics are needed to overcome the challenge of continually evolving bacterial resistance. This has led to a renewed interest in mechanistic studies of once popular antibiotics like chloramphenicol (CAM). Chloramphenicol acetyltransferases (CATs) are enzymes that covalently modify CAM, rendering it inactive against its target, the ribosome, and thereby causing resistance to CAM. Of th...

Mixed Lithium Amide–Lithium Halide Compounds: Unusual Halide-Deficient Amido Metal Anionic Crowns**

Substrate positioning controls the partition between halogenation and hydroxylation in the aliphatic halogenase, SyrB2.

The alpha-ketoglutarate-dependent hydroxylases and halogenases employ similar reaction mechanisms involving hydrogen-abstracting Fe(IV)-oxo (ferryl) intermediates. In the halogenases, the carboxylate residue from the His(2)(Asp/Glu)(1) "facial triad" of iron ligands found in the hydroxylases is replaced by alanine, and a halide ion (X(-)) coordinates at the vacated site. Halogenation is thought...

Flavin redox chemistry precedes substrate chlorination during the reaction of the flavin-dependent halogenase RebH.

The flavin-dependent halogenase RebH catalyzes chlorination at the C7 position of tryptophan as the initial step in the biosynthesis of the chemotherapeutic agent rebeccamycin. The reaction requires reduced FADH(2) (provided by a partner flavin reductase), chloride ion, and oxygen as cosubstrates. Given the similarity of its sequence to those of flavoprotein monooxygenases and their common cosu...