4usz

Publication Abstract from PubMed

Vanadium haloperoxidases (VHPO) are key enzymes that oxidize halides and are involved in the biosynthesis of organo-halogens. Up to now only chloro-(VCPO) and bromoperoxidases (VBPO) have been structurally characterized, mainly from Eukaryotic species. Three putative VHPO genes were predicted in the genome of the flavobacterium Zobellia galactanivorans, a marine bacterium associated with macroalgae. In a phylogenetic analysis, these putative bacterial VHPO are closely related to other VHPO from diverse bacterial phyla, but cluster independently from eukaryotic algal VBPO and fungal VCPO. Two of these bacterial VHPO, heterogeneously produced in E. coli, were found to be strictly specific for iodide oxidation. The crystal structure of one of these vanadium-dependent iodoperoxidases, Zg-VIPO1, was solved by Multi-wavelength Anomalous Diffraction at 1.8 A, revealing a monomeric structure mainly folded into alpha-helices. This 3D structure is relatively similar to those of VCPO of the fungus Curvularia inaequalis and of Streptomyces sp., and superimposable onto the dimeric structure of algal VBPO. Surprisingly, the vanadate binding site of Zg-VIPO1 is strictly conserved with the fungal VCPO active site. Using site-directed mutagenesis we showed that specific amino-acids and the associated hydrogen-bonding network around the vanadate center are essential for the catalytic properties and also for the iodide specificity of Zg-VIPO1. Altogether, phylogeny and structure-function data support the finding that iodoperoxidase activities evolved independently in bacterial and algal lineages, and this sheds light on the evolution of the VHPO enzyme family.

The Bacterial Vanadium Iodoperoxidase from the Marine Flavobacteriaceae Zobellia galactanivorans Reveals Novel Molecular and Evolutionary Features of Halide Specificity in this Enzyme Family.,Fournier JB, Rebuffet E, Delage L, Grijol R, Meslet-Cladiere L, Rzonca J, Potin P, Michel G, Czjzek M, Leblanc C Appl Environ Microbiol. 2014 Sep 26. pii: AEM.02430-14. PMID:25261522^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.