Resonance Raman investigations of chloroperoxidase, horseradish peroxidase, and cytochrome c using Soret band laser excitation

Remba, R.D.; Champion, P. M.; Fitchen, D. B.; Chiang, R.; Hager, Lowell P.

doi:10.1021/bi00578a023

Cited by 53 publications

(26 citation statements)

References 26 publications

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“…Both the 10 and 3 frequencies (1624 and 1488 cm Ϫ1 ) of the native 5chs P450 cam are slightly lower than those expected for the typical ferric 5chs hemes. Similar low frequency shifts of 10 and 3 modes have been reported for other 5chs hemes employing a Cys Ϫ axial ligand (42,43).…”

Section: Absorption Spectral Changes Ofsupporting

confidence: 82%

Refolding Processes of Cytochrome P450cam from Ferric and Ferrous Acid Forms to the Native Conformation

Egawa

Hishiki

Ichikawa

et al. 2004

Journal of Biological Chemistry

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Changes in heme coordination state and protein conformation of cytochrome P450 cam (P450 cam ), a b-type heme protein, were investigated by employing pH jump experiments coupled with time-resolved optical absorption, fluorescence, circular dichroism, and resonance Raman techniques. We found a partially unfolded form (acid form) of ferric P450 cam at pH 2.5, in which a Cys ؊ -heme coordination bond in the native conformation was ruptured. When the pH was raised to pH 7.5, the acid form refolded to the native conformation through a distinctive intermediate. Formations of similar acid and intermediate forms were also observed for ferrous P450 cam . Both the ferric and ferrous forms of the intermediate were found to have an unidentified axial ligand of the heme at the 6th coordination sphere, which is vacant in the high spin ferric and ferrous forms at the native conformation. For the ferrous form, it was also indicated that the 5th axial ligand is different from the native cysteinate. The folding intermediates identified in this study demonstrate occurrences of non-native coordination state of heme during the refolding processes of the large b-type heme protein, being akin to the well known folding intermediates of cytochromes c, in which c-type heme is covalently attached to a smaller protein.

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Section: Absorption Spectral Changes Ofsupporting

confidence: 82%

Refolding Processes of Cytochrome P450cam from Ferric and Ferrous Acid Forms to the Native Conformation

Egawa

Hishiki

Ichikawa

et al. 2004

Journal of Biological Chemistry

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“…Resonance Raman frequencies for CPO are similar to those of HRP. However, unusually low m 4 values are found for ferrous CPO and the CPO-II intermediate, and are considered to be the result of strong electron donation by the axial thiolate [137,138,186]. Though m 11 and m 37 exhibit substantial upshifts for CPO-I relative to CPO-II, the upshift of the m 2 mode is not as great as seen for HRP-I.…”

Section: Discussionmentioning

confidence: 91%

Resonance Raman spectroscopy of oxoiron(IV) porphyrin π-cation radical and oxoiron(IV) hemes in peroxidase intermediates

Terner¹,

Palaniappan²,

Gold³

et al. 2006

Journal of Inorganic Biochemistry

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“…Stern and Peisach (46) first showed that a long wavelength Soret absorption band signifies the presence of a thiolate heme iron ligand in heme proteins. The presence of thiolate ligands in native CPO and P450 cytochromes has been confirmed by extensive spectroscopic techniques (22,(47)(48)(49)(50)) and x-ray crystallographic analysis (25,26). The Soret band for the ferrous-CO complexes of heme proteins containing an imidazole proximal ligand centers at 418-420 nm (51).…”

Section: Methodsmentioning

confidence: 91%

Replacement of the proximal heme thiolate ligand in chloroperoxidase with a histidine residue

Mroczko

Manoj

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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Chloroperoxidase is a versatile heme enzyme which can cross over the catalytic boundaries of other oxidative hemoproteins and perform multiple functions. Chloroperoxidase, in addition to catalyzing classical peroxidative reactions, also acts as a P450 cytochrome and a potent catalase. The multiple functions of chloroperoxidase must be derived from its unique active site structure. Chloroperoxidase possesses a proximal cysteine thiolate heme iron ligand analogous to the P450 cytochromes; however, unlike the P450 enzymes, chloroperoxidase possesses a very polar environment distal to its heme prosthetic group and contains a glutamic acid residue in close proximity to the heme iron. The presence of a thiolate ligand in chloroperoxidase has long been thought to play an essential role in its chlorination and epoxidation activities; however, the research reported in this paper proves that hypothesis to be invalid. To explore the role of Cys-29, the amino acid residue supplying the thiolate ligand in chloroperoxidase, Cys-29 has been replaced with a histidine residue. Mutant clones of the chloroperoxidase genome have been expressed in a Caldariomyces fumago expression system by using gene replacement rather than gene insertion technology. C. fumago produces wild-type chloroperoxidase, thus requiring gene replacement of the wild type by the mutant gene. To the best of our knowledge, this is the first time that gene replacement has been reported for this type of fungus. The recombinant histidine mutants retain most of their chlorination, peroxidation, epoxidation, and catalase activities. These results downplay the importance of a thiolate ligand in chloroperoxidase and suggest that the distal environment of the heme active site plays the major role in maintaining the diverse activities of this enzyme.

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Resonance Raman investigations of chloroperoxidase, horseradish peroxidase, and cytochrome c using Soret band laser excitation

Cited by 53 publications

References 26 publications

Refolding Processes of Cytochrome P450cam from Ferric and Ferrous Acid Forms to the Native Conformation

Refolding Processes of Cytochrome P450cam from Ferric and Ferrous Acid Forms to the Native Conformation

Resonance Raman spectroscopy of oxoiron(IV) porphyrin π-cation radical and oxoiron(IV) hemes in peroxidase intermediates

Replacement of the proximal heme thiolate ligand in chloroperoxidase with a histidine residue

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