1eb7

CRYSTAL STRUCTURE OF THE DI-HAEM CYTOCHROME C PEROXIDASE FROM PSEUDOMONAS AERUGINOSA

spinqualitylabelsall models 1eb7, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1eb7 is a 1 chain structure with sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA, HEC Activity: Cytochrome-c peroxidase, with EC number 1.11.1.5 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed BACKGROUND: Cytochrome c peroxidase from Pseudomonas aeruginosa (PsCCP) represents a new class of peroxidases which work without the need to create a semi-stable free radical for catalysis. The enzyme is located in the bacterial periplasm where its likely function is to provide protection against toxic peroxides. The soluble 323-residue single polypeptide chain contains two covalent c-type haems with very different properties: one of them is a low-potential (-330 mV) centre where hydrogen peroxide is reduced (the peroxidatic site); the other is a high-potential (+320 mV) centre which feeds electrons to the peroxidatic site from soluble electron-shuttle proteins such as cytochrome c and azurin. RESULTS: The crystal structure of the oxidized form of PsCCP has been determined to 2.4 A resolution by multiple isomorphous replacement, and refined to an R-factor of 19.2%. PsCCP is organized into two domains, both of them containing a covalent c-haem in a structure reminiscent of class 1 cytochromes c. The domains are related by a quasi-twofold axis. The domain interface holds a newly discovered calcium-binding site with an unusual set of ligands. CONCLUSIONS: The likely function of the calcium site is to maintain the structural integrity of the enzyme and/or to modulate electron transfer between the two haem domains. The low-potential haem has two histidine axial ligands (His55 and His71) and the high-potential haem is ligated by His201 and Met275. There are no polar residues at the peroxidatic site in the inactive oxidized enzyme. The structure suggests that, in the half-reduced functional form of the enzyme, the low-potential haem has to shed His71 in order to make the enzyme catalytically competent. This process is likely to trigger a reorganization of the active site, and may introduce a new residues into the haem pocket. Crystal structure of the di-haem cytochrome c peroxidase from Pseudomonas aeruginosa.,Fulop V, Ridout CJ, Greenwood C, Hajdu J Structure. 1995 Nov 15;3(11):1225-33. PMID:8591033 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome c peroxidase

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