Structural characterization of Paracoccus denitrificans cytochrome c peroxidase and assignment of the low and high potential heme sites.
The amino acid sequence of the diheme cytochrome c peroxidase from Paracoccus denitrificans has been determined as the result of sequence analysis of peptides generated by chemical and enzymatic cleavages of the apoprotein. The sequence shows 60% similarity to the cytochrome c peroxidase from Pseudomonas aeruginosa, 39% similarity to an open reading frame encoding a putative triheme c-type cytochrome in Escherichia coli, and remote similarity to the MauG proteins from two methylotrophic bacteria. It is proposed, on the basis of the pattern of conserved residues in the sequences, that a change in iron coordination in the N-terminal heme domain may accompany reduction to the active mixed valence state, a change which may be accompanied by conformational adjustments in the highly conserved interface between the N- and C-terminal domains. These conformational adjustments may also lead to the appearance of a second Ca2+ binding site in the mixed valence enzyme. The exposed edge of the heme in the C-terminal domain is surrounded by several different patterns of charged residues in the Paracoccus and Pseudomonas enzymes, and this is consistent with the interaction of the former with the highly positively charged front face of the donor cytochrome c-550.
Hu
W
W
Department of Biochemistry, State University of Gent, B-9000, Gent, Belgium.
Van Driessche
G
G
Devreese
B
B
Goodhew
C F
CF
McGinnity
D F
DF
Saunders
N
N
Fulop
V
V
Pettigrew
G W
GW
Van Beeumen
J J
JJ
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D003578:Cytochrome-c Peroxidase / Q000737:chemistry* / Q000378:metabolism; D006418:Heme / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000201:enzymology*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000201:enzymology; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D006418:Heme; D003578:Cytochrome-c Peroxidase