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spinqualitylabelsall models 1itk, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of catalase-peroxidase from Haloarcula marismortui

Overview

Catalase-peroxidase is a member of the class I peroxidase superfamily. The, enzyme exhibits both catalase and peroxidase activities to remove the, harmful peroxide molecule from the living cell. The 2.0 A crystal, structure of the catalase-peroxidase from Haloarcula marismortui (HmCP), reveals that the enzyme is a dimer of two identical subunits. Each subunit, is composed of two structurally homologous domains with a topology similar, to that of class I peroxidase. The active site of HmCP is in the, N-terminal domain. Although the arrangement of the catalytic residues and, the cofactor heme b in the active site is virtually identical to that of, class I peroxidases, the heme moiety is buried inside the domain, similar, to that in a typical catalase. In the vicinity of the active site, novel, covalent bonds are formed among the side chains of three residues, including that of a tryptophan on the distal side of the heme. Together, with the C-terminal domain, these covalent bonds fix two long loops on the, surface of the enzyme that cover the substrate access channel to the, active site. These features provide an explanation for the dual activities, of this enzyme.

About this Structure

1ITK is a Single protein structure of sequence from Haloarcula marismortui with SO4, CL, UNX and HEM as ligands. Active as Catalase, with EC number 1.11.1.6 Full crystallographic information is available from OCA.

Reference

The 2.0 A crystal structure of catalase-peroxidase from Haloarcula marismortui., Yamada Y, Fujiwara T, Sato T, Igarashi N, Tanaka N, Nat Struct Biol. 2002 Sep;9(9):691-5. PMID:12172540

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