InterPro: IPR016118 Phosphatidic acid phosphatase/chloroperoxidase, N-terminal

This entry represents an alpha helical domain is found in type 2 phosphatidic acid phosphatases [1] and at the N-terminal of chloroperoxidases. The structure of chloroperoxidase from the fungus, Curvularia inaequalis, consists of a duplication, containing two core alpha-helical bundles arranged as in other family dimer [2]. Chloroperoxidases (EC:1.11.1.10) use a haem cofactor to bring about the chlorination of a range of organic molecules, forming stable C-Cl bonds. The enzyme active sites of the vanadium haloperoxidases have shown some conservation with a completely different set of enzymes, the phosphatidic acid phosphatases (EC:3.1.3.4). This sub-group of acid phosphatases are histidine phosphatase, using histidine for the nucleophilic attack in the first step of the reaction [3]. Amino acid residues involved in binding phosphate/vanadate are conserved between the two families, supporting a proposal that vanadium passes through a tetrahedral intermediate during the reaction mechanism.