Structural and functional features of Pseudomonas cytochrome c peroxidase

A reinvestigation of the covalent structure of Pseudomonas aeruginosa cytochrome c peroxidase

“…in Paracoccus ,fi ~itrificans cytochrome c-550 [9]). However, since a methionin: as the sixth ligand is nearly always associated with a high retox potential of the haem, this interpretation would imply tl~ it PaCCP has two haems with high redox potential which is in contrast with the observation that the haems act at redox p~ tentials differing as much as 600 mV [2]. Consequently, this se :ond possibility is less likely although there is a precedent for a low potential haem with a His-Met ligand structure [10].…”

“…F aally, we can not exclude the possibility of a mechanism in wuch Met-275 ligates the second haem site while His-116 lig~tes the first haem. The relative configuration of the high and Io ~¢ redox potential sites would then be as originally suggested bx Ellfolk et al [2].…”

“…The authors proposed that the first half of the polypeptide chain contains the low potential haem-binding region that react.. with the hydrogen peroxide, and that the second half contaft,s the high potential haem-binding region that interacts with the reduced electron donor protein of CCP. Carrying out high pre,=ision mass analysis of Pa CCP, we recently noticed that its mo ecular mass is some 2 kDa higher than the calculated mass of I he amino acid sequence published by Ellfolk et al [2]. We now report the complete amino acid sequence of PaCCP, including the proof of the covalent linkage of the two haem groaps, based on the evidence obtained from Edman degradatiol in combination with mass analysis of the sequenced peptides.…”

“…R6nnberg et al [1] originally reported that the polypel'.tide is 302 amino acids long containing two typical haem c-b,nding sites (Cys-X-Y-Cys-His), and that it had six positions whure the presence of two residues betrayed micro heterogeneity. In a subsequent paper, Ellfolk et al [2] corrected this sequence by reducing the number of heterogeneous positions to two. The authors proposed that the first half of the polypeptide chain contains the low potential haem-binding region that react.. with the hydrogen peroxide, and that the second half contaft,s the high potential haem-binding region that interacts with the reduced electron donor protein of CCP.…”

Structural and Mutagenesis Studies on the Cytochrome c Peroxidase from Rhodobacter capsulatus Provide New Insights into Structure-Function Relationships of Bacterial Di-heme Peroxidases

“…aeruginosa and Paracoccus pantotrophus (5,8,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Spectroscopic studies of these enzymes suggest the existence of a complex reaction mechanism that involves changes in the redox and spin states of the heme groups.…”