Vanadium haloperoxidases

It is also of interest to point out that the amino acid sequence and structure of the active site of vanadium haloperoxidases is conserved within several families of phosphatases, with conservation of the amino acids involved in vanadate binding in one and phosphate binding in the other. 

Enzymes requiring vanadium for catalytic activity. Perhaps the best studied of these are the vanadium-dependent nitrogenases [EC 1.18.6.1]. Other vanadium-dependent enzymes include vanadium haloperoxidase, vanadium chloroperoxidase, and vanadium bromoper-oxidase. In the vanadium chloroperoxidase and bromo-peroxidase reactions, the vanadium(V) is coordinated in a trigonal bipyramidal site to a histidyl residue, three nonprotein oxygens, and, presumably, to a hydroxide. 

For electron-rich substrates, nature often uses flavin-dependent halogenases (e.g. chlorotetracycline), vanadium haloperoxidases (snyderol, Figure 7.4) or heme-iron haloperoxidases (tetraiodothyronine. Figure 7.4) for this role (Figure 7.5). For electron-deficient molecules such as alkanes, mononuclear iron... 

The ubiquitous hemoprotein chloroperoxidase (CPO) (1) continues to be of great mechanistic and practical interest following its isolation more than 40 years ago from Caldariomyces fumago (2138). The CPO gene from this filamentous fungus has been isolated and sequenced (2139), an active recombinant CPO has been produced (2140), and the crystal structure of this CPO has been determined (2141, 2142). The fungus Curvularia inaequalis contains a vanadium CPO, which has been characterized (primary and X-ray structure) (Fig. 4.1) (2143-2147), as has the vanadium haloperoxidase from Corallina officinalis (2324). This enzyme has also been studied by density functional theory lending support to the proposed mechanism of action (Scheme 4.1) (2325). A related vanadium CPO, which shares 68% primary structural identity with the Curvularia inaequalis CPO, is produced... 

Butler A (1998) Vanadium Haloperoxidases. Curr Opin Chem Biol 2 279... 

Butler A (1999) Mechanistic Considerations of the Vanadium Haloperoxidases. Coord Chem Rev 187 17... 

Carter-Franklin JN, Parrish JD, Tschirret-Guth RA, Little RD, Butler A (2003) Vanadium Haloperoxidase-Catalyzed Bromination and Cyclization of Terpenes. J Am Chem Soc 125 3688... 

Almeida MG, Humanes M, Melo R, Silva JA, Frausto da Silva JJR, Wever R (2000) Purification and Characterisation of Vanadium Haloperoxidases from the Brown Alga Pelvetia canaliculata. Phytochemistry 54 5... 

Zampella G, Fantucci P, Pecoraro VL, De Gioia L (2005) Reactivity of Peroxo Forms of the Vanadium Haloperoxidase Cofactor. A DFT Investigation. J Am Chem Soc 127 953... 

A. Dalby, and M. Isupov, Structural and functional comparisons between vanadium haloperoxidase and add phosphatase enzymes,/. Mol. Recognit. 2002, 15, 291-296. 

The emphasis of this review chapter will be on the reactivity of the vanadium haloperoxidases. A brief summary of the molecular properties of these en-... 

The vanadium haloperoxidases function first by coordination of dihydrogen peroxide followed by oxidation of the halide (Scheme 7). The consensus seems to be that the vanadium center functions as a Lewis acid, remaining in the 5+ oxidation state, as opposed to functioning as an electron transfer catalyst, although it should be pointed out that the reduction potential of the vanadate center has not been measured. 

Hamstra, B.J., G.J. Colpas, and V.L. Pecoraro. 1998. Reactivity of dioxovanadium(V) complexes with hydrogen peroxide Implications for vanadium haloperoxidase. Inorg. Chem. 37 949-955. 

Guevara-Garcia, J.A., N. Barba-Behrens, R. Contreras, and G. Mendosa-Diaz. 1998. Bis-peroxo-oxovanadium(V) complexes of histidine-containing peptides as models for vanadium haloperoxidases. In Vanadium Compounds Chemistry, Biochemistry and Therapeutic Applications. A.S. Tracey and D.C. Crans (Eds). American Chemical Society, Washington, D.C. 126-35. 

Wever, R. 2004. Vanadium haloperoxidases and their role in the formation of chlorinated compounds. Euro Chlor workshop on soil chlorine chemistry. Workshop proceedings, Euro chior, Brussels, pp. 29-35. 

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