Resonance Raman characterization of heme Fe(IV)=O groups of intermediates of yeast cytochrome C peroxidase and lactoperoxidase

Reczek, Catherine M.; Sitter, Andres J.; Terner, James

doi:10.1016/0022-2860(89)80004-3

Cited by 61 publications

(59 citation statements)

References 72 publications

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“…The Fe-O vibration for the heme ferryl species is on the lower side of the range reported for heme ferryl species (51). These values are very similar to those reported for lactoperoxidase (745 cm Ϫ1 ) and cytochrome c peroxidases (753 cm Ϫ1 ) (52) and may indicate weakening of the Fe IV AO bond by hydrogen bonding or a strong trans effect of the covalently attached proximal imidazole tail (52). The occurrence of the bis-ferryl intermediate after a peroxide intermediate indicates a homolytic OOO bond cleavage occurring in this complex.…”

Section: Discussionsupporting

confidence: 80%

“…One band is observed at 808 cm Ϫ1 , and the other is observed at 756 cm Ϫ1 ; the bands shift by 32 cm Ϫ1 and 25 cm Ϫ1 , respectively. Fe-O vibrations for Fe IV AO porphyrin species have been observed between 745 cm Ϫ1 and 850 cm Ϫ1 (51,52), and those for nonheme ferryl species are observed between 800 and 840 cm Ϫ1 depending on spin state and different trans ligands (53)(54)(55)(56). The presence of only these 2 oxygen isotope-sensitive bands at 756 cm Ϫ1 and 808 cm Ϫ1 indicate that there are 2 distinct ferryl species in this intermediate.…”

Section: Resultsmentioning

confidence: 96%

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O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Collman

Dey

Yang

et al. 2009

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

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O2 reactivity of a functional NOR model is investigated by using electrochemistry and spectroscopy. The electrochemical measurements using interdigitated electrodes show very high selectivity for 4e O2 reduction with minimal production of partially reduced oxygen species (PROS) under both fast and slow electron flux. Intermediates trapped at cryogenic temperatures and characterized by using resonance Raman spectroscopy under single-turnover conditions indicate that an initial bridging peroxide intermediate undergoes homolytic OOO bond cleavage generating a trans heme/nonheme bis-ferryl intermediate. This bis ferryl species can oxygenate 2 equivalents of a reactive substrate.C ytochrome c oxidase (CcO) and nitric oxide reductase (NOR) belong to the heme copper oxidase superfamily of enzymes (1, 2). CcO is the terminal enzyme in the respiratory chain of higher organisms, located in their mitochondrial membrane, that reduces O 2 to H 2 O as source of energy. The O 2 reduction process in CcO generates a pH gradient across the bilayer membrane, which provides the driving force for ATP synthesis. The bimetallic active site of CcO has a heme ligated to the protein by a proximal histidine ligand and a distal Cu B site coordinated by 3 histidine ligands ( Fig. 1) (3). In addition to the bimetallic site, there is a conserved tyrosine ligand covalently attached to one of the histidines coordinated to Cu B (4, 5). The NORs are the older member of the family and are found in bacteria using NO 3 Ϫ as source of energy instead of O 2 (2, 6, 7). Although there are no high-resolution crystal structures of NOR, biochemical studies and computer modeling indicate that these enzymes have a histidine-ligated heme, quite like the CcOs, and a distal Fe B , unlike Cu B in CcO, coordinated by 3 histidines ( Fig. 1) (8-10). NORs do not have the conserved tyrosine residue of CcO but have a few conserved key glutamate residues (11,12). Although the NOR enzymes are proposed to have specific proton channels, they are probably not involved in generating proton gradients (13-16).These 2 enzymes exhibit complementary reactivity toward 2 very significant diatomic molecules in nature; O 2 and NO. In eukaryotes CcO (aa 3 type) reduces O 2 to H 2 O and is reversibly but strongly inhibited by [17][18][19][20]. Several other CcOs (ba 3 , caa 3 , cbb 3 ) are reported to exhibit limited (Ͻ1%) NOR activity, i.e., reduce NO to N 2 O (7, 21). On the other hand, NORs that reduce NO to N 2 O are reversibly but strongly inhibited by O 2 , and some of them show modest (Ϸ10%) O 2 reduction activity (12). The parallels in their reactivities toward O 2 and NO and similarities in their secondary structures have led to a hypotheses regarding NOR's and CcO's similar evolutionary origins (6,22).Electrochemistry is a very powerful technique that can provide fundamental insights into reaction mechanisms of redox catalysts (23-27). Conventionally, a catalyst is deposited on a conducting electrode material (e.g., graphite); however, this approach does not allow site isola...

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Section: Discussionsupporting

confidence: 80%

Section: Resultsmentioning

confidence: 96%

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Collman

Dey

Yang

et al. 2009

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

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“…This assignment is consistent with the frequencies reported in the literature for catalytic intermediates of classical peroxidases. [11][12][13][14][15][16] In the absence of the reference RR spectra of Cpd I and Cpd II in DyPs, the assignment of the 1378 cm À1 and 1508 cm À1 modes to the oxyferryl Fe(IV)QO porphyrin p cation is supported by the evidence from our previous work: (i) electronic absorption spectra, which reveal a fingerprint of stable Cpd I in the reaction of PpDyP with 1-3 equivalents of H 2 O 2 in solution; [8][9][10] 8 The n 4 /n 3 values that we observe here are slightly higher than those reported for Cpd I in the literature, 11 which may be an intrinsic property of DyPs, or an indication of Cpd II. For instance, n 4 and n 3 modes of Cpd I in HRP were found at 1373-1376 and 1505 cm À1 , respectively, but at 1379 and 1510 cm À1 in Cpd II.…”

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confidence: 99%

Surface enhanced resonance Raman detection of a catalytic intermediate of DyP-type peroxidase

Todorović

Hildebrandt

Martins

2015

Phys. Chem. Chem. Phys.

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We report herein the vibrational spectroscopic characterisation of a catalytic intermediate formed by the reaction of H 2 O 2 with DyP-type peroxidase immobilised on a biocompatible coated metal support.The SERR spectroscopic approach is of general applicability to other peroxidases which form relatively stable catalytic intermediates.Dye-decolourising peroxidases (DyPs) are novel heme peroxidases, the primary sequence, structural and mechanistic properties of which are unrelated to those of other known peroxidases. [1][2][3][4][5][6][7][8][9][10] They lack the distal histidine that is highly conserved in classical peroxidases and which acts as an acid/base catalyst in the reduction of hydrogen peroxide to water. DyPs are classified into four phylogenetically distinct classes (A-D); their physiological role is not fully established yet and it appears to be subfamilydependent. 1-10 DyP from Pseudomonas putida MET94 (PpDyP) is an extremely versatile B-type DyP, capable of efficient oxidation of a wide range of anthraquinonic and azo dyes, phenolic substrates, the non-phenolic veratryl alcohol and even manganese and ferrous ions. 8 In the reaction with H 2 O 2 , PpDyP forms a stable Compound I (Cpd I) at a rate of 1.4 AE 0.3 Â 10 6 M À1 s À1 , comparable to those of classical peroxidases and other DyPs. 8 The intermediate is, like in other DyPs, surprisingly long-living, with a half-life of B60 min, as demonstrated by electronic absorption spectroscopy. 9 Upon immobilisation on biocompatible metal supports, PpDyP is capable of efficient electrocatalytic activity in the presence of hydrogen peroxide. The enzyme is therefore a promising candidate for the design of bio-electronic devices with unique DyP-type peroxidase substrate specificity. 9,10 Resonance Raman (RR) spectroscopy has been extensively used in the detection and characterisation of peroxidase and catalase-peroxidase catalytic intermediates, and RR spectroscopic fingerprints of Cpd I (two equivalent oxidised resting ferric state) and Cpd II (one equivalent oxidised resting ferric state) are well established. [11][12][13][14][15][16] However, a strong fluorescence impeded the RR studies of PpDyP intermediates. Here, we have probed catalytic intermediate species of immobilised PpDyP by surface enhanced RR (SERR) spectroscopy. The SERR spectra of heme proteins immobilised on nanostructured Ag surfaces exclusively display the cofactor signals of the adsorbed molecules. In addition, close proximity of the molecule to the metal surface can efficiently quench fluorescence. 17 Like in RR spectroscopy, SERR signals include, inter alia, the core-size marker bands (e.g. n 4 , n 3 , n 2 , n 10 ) which are specifically enhanced upon excitation in resonance with the Soret absorption band of the porphyrin. The frequencies of these modes are indicative of the redox and spin states and the coordination pattern of the heme iron.We have previously shown that the high frequency region of RR spectra of the resting PpDyP in solution displays broad marker bands, indicative of t...

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“…Such a rate increase could be attributed to more favourable electrostatic interactions at pH 5.0 since CCP has a pI = 5.26 (17), suggesting that proton transfer is not rate determining in the electron-transfer reactions of CCP" at neutral pH. This is consistent with the proposed site of protonation in CpdII being the oxygen atom of the FeIV=O moiety (26,27). Therefore, the smaller k r for CpdIYCCPU1 compared to that for CCP1'/CCPH1 may be due to the existence of (partially) rate-limiting proton transfer and FetV=O bond cleavage on reduction of CpdII.…”

Section: Discussionmentioning

confidence: 56%

“…Resonance Raman data indicate that the Fe atom is high spin and 5-coordinate in both CCP" and CCP1" (25), whereas the F~" = O heme is 6-coordinate, low spin (26). Since cleavage of the FeIV=O bond occurs on reduction of CpdII, the inner-sphere reorganizational energy for the CpdIVCCPH1 couple is expected to be greater than that for CCP"/CCP"'.…”

Section: Discussionmentioning

confidence: 99%

Reductions by ferrocytochrome c peroxidase: 5. Kinetics of ferricyanide reduction

Cheung¹,

English²

1995

Can. J. Chem.

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Abstract:The kinetics of reduction of femcyanide by yeast ferrocytochrome c peroxidase (CPPI') were investigated as a function of ionic strength in phosphate buffers at pH 7.0 and 25 3= 1°C. The observed bimolecular rate constant (k12) is 8.4 x 10" M-I s-I in 0.1 M phosphate. The dependence of the reaction rate on ionic strength indicates a change of -9 on the protein at pH 7.0, which is in good agreement with the total charge of -1 1 estimated for CCP" from its amino acid content. Substituting k12 at infinite ionic strength (kz) into the Marcus cross relation yields an electron self-exchange rate constant ( k: ) for the Felll/Fell couple of CCP of 7.2 x M-' s-I. This value is over four orders of magnitude higher than that calculated for the ~e'~/Fe'll couple of CCP from literature data for cross-reactions with ferrocyanide at pH 7.0. Possible reasons for the large difference in the two CCP k;"; values are discussed. Literature data also allowed k;"; values for various other heme proteins to be determined from their cross-reactions with femcyanide. The calculated rate constants vary by eight orders of magnitude, and the variation of k; with protein structure suggests that the redox reactivity of ferrous heme proteins towards femcyanide is dependent on the spin state and coordination of iron, as well as on the accessibility of the heme.

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Resonance Raman characterization of heme Fe(IV)=O groups of intermediates of yeast cytochrome C peroxidase and lactoperoxidase

Cited by 61 publications

References 72 publications

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

Surface enhanced resonance Raman detection of a catalytic intermediate of DyP-type peroxidase

Reductions by ferrocytochrome c peroxidase: 5. Kinetics of ferricyanide reduction

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Resonance Raman characterization of heme Fe(IV)=O groups of intermediates of yeast cytochrome C peroxidase and lactoperoxidase

Cited by 61 publications

References 72 publications

O 2 reduction by a functional heme/nonheme bis-iron NOR model complex

O 2 reduction by a functional heme/nonheme bis-iron NOR model complex

Surface enhanced resonance Raman detection of a catalytic intermediate of DyP-type peroxidase

Reductions by ferrocytochrome c peroxidase: 5. Kinetics of ferricyanide reduction

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O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex

O ₂ reduction by a functional heme/nonheme bis-iron NOR model complex