2VHD

Crystal Structure Of The Di-Haem Cytochrome C Peroxidase From Pseudomonas aeruginosa - Mixed Valence Form

Summary for 2VHD

• Entry DOI: 10.2210/pdb2vhd/pdb
• Related: 1EB7
• Descriptor: CYTOCHROME C551 PEROXIDASE, HEME C, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: iron, heme, transport, peroxidase, metal-binding, oxidoreductase, electron transport
• Biological source: PSEUDOMONAS AERUGINOSA
• Total number of polymer chains: 2
• Total formula weight: 72705.04

Authors

Echalier, A.,Brittain, T.,Wright, J.,Boycheva, S.,Mortuza, G.B.,Fulop, V.,Watmough, N.J. (deposition date: 2007-11-20, release date: 2008-02-12, Last modification date: 2024-11-13)

Primary citation

Echalier, A.,Brittain, T.,Wright, J.,Boycheva, S.,Mortuza, G.B.,Fulop, V.,Watmough, N.J.
Redox-Linked Structural Changes Associated with the Formation of a Catalytically Competent Form of the Diheme Cytochrome C Peroxidase from Pseudomonas Aeruginosa
Biochemistry, 47:1947-, 2008

PubMed Abstract: A 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 10(10) 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.

PubMed: 18217775
DOI: 10.1021/BI702064F

Experimental method

X-RAY DIFFRACTION (2.3 Å)