The Quantum Mixed-Spin Heme State of Barley Peroxidase:A Paradigm for Class III Peroxidases

Howes, Barry D.; Schiødt, Christine Bruun; Welinder, Karen G.; Marzocchi, Mario P.; Ma, Jie; Zhang, Jun; Shelnutt, John A.; Smulevich, Giulietta

doi:10.1016/s0006-3495(99)76905-5

Cited by 81 publications

(139 citation statements)

References 57 publications

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“…The most striking difference between the spectra of native and Ca 2ϩ -depleted HRPC is the higher frequencies of the core size marker bands of the Ca 2ϩ -depleted form. This immediately indicates the presence of a QS heme state, which is more fully expressed compared with that of the native protein having a greater proportion of IS in the quantum mechanical admixture, since no bands due to an LS heme were detected in the corresponding absorption spectrum (22)(23)(24). All subsequent reference to the QS state of the Ca 2ϩ -depleted enzyme will be in regard to this fully expressed QS state and not that of the native protein in which only a low level of IS is apparently present.…”

Section: Electronic Absorption and Resonance Raman Of Ferric Enzymes-mentioning

confidence: 94%

The Critical Role of the Proximal Calcium Ion in the Structural Properties of Horseradish Peroxidase

Howes

Feis

Raimondi³

et al. 2001

Journal of Biological Chemistry

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The extent to which the structural Ca 2؉ ions of horseradish peroxidase (HRPC) are a determinant in defining the heme pocket architecture is investigated by electronic absorption and resonance Raman spectroscopy upon removal of one Ca 2؉ ion. The Fe(III) heme states are modified upon Ca 2؉ depletion, with an uncommon quantum mechanically mixed spin state becoming the dominant species. Ca 2؉ -depleted HRPC forms complexes with benzohydroxamic acid and CO which display spectra very similar to those of native HRPC, indicating that any changes to the distal cavity structural properties upon Ca 2؉ depletion are easily reversed. Contrary to the native protein, the Ca 2؉ -depleted ferrous form displays a low-spin bis-histidyl heme state and a small proportion of high-spin heme. Furthermore, the (Fe-Im) stretching mode downshifts 27 cm ؊1 upon Ca 2؉ depletion revealing a significant structural perturbation of the proximal cavity near the histidine ligand. The specific activity of the Ca 2؉ -depleted enzyme is 50% that of the native form. The effects on enzyme activity and spectral features observed upon Ca 2؉ depletion are reversible upon reconstitution. Evaluation of the present and previous data firmly favors the proximal Ca 2؉ ion as that which is lost upon Ca 2؉ depletion and which likely plays the more critical role in regulating the heme pocket structural and catalytic properties.Peroxidases of the plant peroxidase superfamily are hemecontaining enzymes that oxidize a variety of aromatic molecules in the presence of hydrogen peroxide. They include peroxidases of plant, fungal, and prokaryotic origins that can be divided into three classes based on sequence alignment (1).Additional support for such a classification was gained as the crystal structures of representative enzymes of each class became available. Class I contains bacterial peroxidases and peroxidases from plant mitochondria and chloroplasts, for example most ascorbate peroxidases and cytochrome c peroxidase. Class II contains extracellular fungal peroxidases such as Coprinus cinereus peroxidase (a peroxidase essentially identical to Arthromyces ramosus peroxidase) and lignin-degrading peroxidases. Class III contains secretory plant peroxidases, typified by the classical horseradish peroxidase isoenzyme C (HRPC). The peroxidases of classes II and III share a number of structural elements considered to be of importance for maintaining protein stability and activity. These include calciumbinding sites proximal and distal to the heme and four disulfide bridges (1-5); the latter was in different locations in class II with respect to class III peroxidases. These features are absent in class I peroxidases. Class III peroxidases also have a loop insertion in the sequence, composed of the DЈ, FЈ, and FЉ helices, not found in the other classes. The relationship between calcium binding and enzyme inactivation has been treated primarily by studies on lignin peroxidase (LIP) (6, 7), manganese peroxidase (MNP) (8, 9), and HRPC (10, 11). Thermal (6) and alkaline (7) i...

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Section: Electronic Absorption and Resonance Raman Of Ferric Enzymes-mentioning

confidence: 94%

The Critical Role of the Proximal Calcium Ion in the Structural Properties of Horseradish Peroxidase

Howes

Feis

Raimondi³

et al. 2001

Journal of Biological Chemistry

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“…11,[18][19][20] Namely, the origin of this unusual heme configuration, also observed in class III plant peroxidases, cytochromes c 0 and catalase peroxidases (e.g. KatG), is not well understood.…”

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confidence: 99%

“…KatG), is not well understood. 11,[18][19][20] We have previously demonstrated that it could be observed in B-, but not in A-type DyPs, and that its abundance sensitively depends on the pH, temperature, and physical state of the enzyme. 10 Here we provide direct experimental evidence that the QS species is capable of reacting with H 2 O 2 and that it is therefore, most likely catalytically competent in PpDyP.…”

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confidence: 99%

“…In addition, SERR detection of catalytic intermediates is possible at ambient temperature in contrast to EPR spectroscopy that is restricted to cryogenic conditions. Thus, SERR spectroscopy avoids temperaturedependent changes of spin state distributions, 9,10,18,19 and is applicable to the EPR-silent Cpd II. 21 As a drawback, SERR spectroscopic identification of intermediates is restricted to species with lifetimes on the minute time scale (e.g.…”

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confidence: 99%

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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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“…Based on structural divergence, the plant peroxidase superfamily is subdivided into three classes. BP1 belongs to class III, typified by the classical horseradish peroxidase isoenzyme C (HRPC) 135 . In common with other heme-containing peroxidases, BP1 catalyzes the following multistep reaction 271 The rate of the BP1 reaction with hydrogen peroxide is very slow at a pH above 5 and increases as the pH is lowered to 3.…”

Section: Peroxidases (Pr-9)mentioning

confidence: 99%

A Review: Biological and Technological Functions of Barley Seed Pathogenesis-Related Proteins (PRs)

Gorjanović

2009

Journal of the Institute of Brewing

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The mature barley seed proteome is dominated by proteins involved in stress responses, including the Pathogenesis-Related proteins (PRs). PRs are currently classified into 17 families. The biochemistry of the PRs families, whose members are constitutively present in barley seed, is surveyed in this paper. These proteins are assumed to protect dormant and germinating seeds against pathogenic microorganisms and pests. The current knowledge on PRs structural and functional properties is summarized in an attempt to illustrate their importance in barley seed innate resistance. At the same time, a platform to understand PRs technological function in cereal foods and in beverage processing and quality is provided.

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The Quantum Mixed-Spin Heme State of Barley Peroxidase:A Paradigm for Class III Peroxidases

Cited by 81 publications

References 57 publications

The Critical Role of the Proximal Calcium Ion in the Structural Properties of Horseradish Peroxidase

The Critical Role of the Proximal Calcium Ion in the Structural Properties of Horseradish Peroxidase

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

A Review: Biological and Technological Functions of Barley Seed Pathogenesis-Related Proteins (PRs)

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