Fig. 1: Central questions on vanadium-dependent haloperoxidase (VHPO) mechanism.

a Schematic representation of the mechanism of the VHPO-catalyzed halogenation. b Structure superimposition of active site residues (green) and residues proximal to the active site (gray) of selected vanadium-dependent haloperoxidases from A. marina (PDB: 5LPC), A. nodosum (PDB: 1QI9), C. officinalis (PDB: 1QHB), C. pulifera (PDB: 1UP8), C. inaequalis (PDB: 1IDQ). The residue nomenclature follows the sequence of the bromoperoxidase of A. marina. The backbone in gray is derived from the crystal structure of A. marina (PDB: 5LPC). c Selected example of a non-selective and a selective halogenation catalyzed by algal VHPOs^38,50 and Streptomyces CNH-189, respectively³⁰. d This work delivers molecular insights gained by single point mutations of R425 and the structure-activity analysis of this mutant.