2vhd
From Proteopedia
Crystal Structure Of The Di-Haem Cytochrome C Peroxidase From Pseudomonas aeruginosa - Mixed Valence Form
Structural highlights
FunctionCCPR_PSEAE Catalyzes the peroxidative oxidation of azurin and cytochrome c551. Likely to provide protection against toxic peroxides. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedA recombinant form of the prototypic diheme bacterial cytochrome c peroxidase (BCCP) from Pseudomonas aeruginosa (PsaCCP) has been expressed in Escherichia coli and purified to homogeneity. This material was used to carry out the first integrated biochemical, spectroscopic and structural investigation of the factors leading to reductive activation of this class of enzymes. A single, tightly bound, Ca2+ ion (K = 3 x 1010 M-1) found at the domain interface of both the fully oxidized and mixed-valence forms of the enzyme is absolutely required for catalytic activity. Reduction of the electron-transferring (high-potential) heme in the presence of Ca2+ ions triggers substantial structural rearrangements around the active-site (low-potential) heme to allow substrate binding and catalysis. The enzyme also forms a mixed-valence state in the absence of Ca2+ ions, but a combination of electronic absorption, and EPR spectroscopies suggests that under these circumstances the low potential heme remains six-coordinate, unable to bind substrate and therefore catalytically inactive. Our observations strongly suggest that the two mixed-valence forms of native PsaCCP reported previously by Foote and colleagues (Foote, N., Peterson, J., Gadsby, P., Greenwood, C., and Thomson, A. (1985) Biochem. J. 230, 227-237) correspond to the Ca2+-loaded and -depleted forms of the enzyme. Redox-Linked Structural Changes Associated with the Formation of a Catalytically Competent Form of the Diheme Cytochrome c Peroxidase from Pseudomonas aeruginosa(,).,Echalier A, Brittain T, Wright J, Boycheva S, Mortuza GB, Fulop V, Watmough NJ Biochemistry. 2008 Feb 19;47(7):1947-1956. Epub 2008 Jan 25. PMID:18217775[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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