scholarly journals Unique Biradical Intermediate in the Mechanism of the Heme Enzyme Chlorite Dismutase

ACS Catalysis ◽  
2021 ◽  
pp. 14533-14544
Author(s):  
Julia Püschmann ◽  
Durga Mahor ◽  
Daniël C. de Geus ◽  
Marc J. F. Strampraad ◽  
Batoul Srour ◽  
...  
Keyword(s):  
Chlorite Dismutase ◽  
Heme Enzyme

scholarly journals Unexpected photosensitivity of the well-characterized heme enzyme chlorite dismutase

2020 ◽  
Vol 25 (8) ◽  
pp. 1129-1138
Author(s):  
Durga Mahor ◽  
Julia Püschmann ◽  
Diederik R. Adema ◽  
Marc J. F. Strampraad ◽  
Peter-Leon Hagedoorn
Keyword(s):  
Visible Light ◽  
Ferric Hydroxide ◽  
Time Range ◽  
Light Illumination ◽  
Stopped Flow ◽  
Heme Enzymes ◽  
Oligomeric State ◽  
Chlorite Dismutase ◽  
Heme Enzyme ◽  
Uv Visible

Abstract Chlorite dismutase is a heme enzyme that catalyzes the conversion of the toxic compound ClO2− (chlorite) to innocuous Cl− and O2. The reaction is a very rare case of enzymatic O–O bond formation, which has sparked the interest to elucidate the reaction mechanism using pre-steady-state kinetics. During stopped-flow experiments, spectroscopic and structural changes of the enzyme were observed in the absence of a substrate in the time range from milliseconds to minutes. These effects are a consequence of illumination with UV–visible light during the stopped-flow experiment. The changes in the UV–visible spectrum in the initial 200 s of the reaction indicate a possible involvement of a ferric superoxide/ferrous oxo or ferric hydroxide intermediate during the photochemical inactivation. Observed EPR spectral changes after 30 min reaction time indicate the loss of the heme and release of iron during the process. During prolonged illumination, the oligomeric state of the enzyme changes from homo-pentameric to monomeric with subsequent protein precipitation. Understanding the effects of UV–visible light illumination induced changes of chlorite dismutase will help us to understand the nature and mechanism of photosensitivity of heme enzymes in general. Furthermore, previously reported stopped-flow data of chlorite dismutase and potentially other heme enzymes will need to be re-evaluated in the context of the photosensitivity. Graphic abstract Illumination of recombinantly expressed Azospira oryzae Chlorite dismutase (AoCld) with a high-intensity light source, common in stopped-flow equipment, results in disruption of the bond between FeIII and the axial histidine. This leads to the enzyme losing its heme cofactor and changing its oligomeric state as shown by spectroscopic changes and loss of activity.

scholarly journals How Active-Site Protonation State Influences the Reactivity and Ligation of the Heme in Chlorite Dismutase

2010 ◽  
Vol 132 (16) ◽  
pp. 5711-5724 ◽  
Author(s):  
Bennett R. Streit ◽  
Béatrice Blanc ◽  
Gudrun S. Lukat-Rodgers ◽  
Kenton R. Rodgers ◽  
Jennifer L. DuBois
Keyword(s):  
Active Site ◽  
Protonation State ◽  
Chlorite Dismutase

scholarly journals Peroxidase-Type Reactions Suggest a Heterolytic/Nucleophilic O–O Joining Mechanism in the Heme-Dependent Chlorite Dismutase

Biochemistry ◽  
2013 ◽  
Vol 52 (40) ◽  
pp. 6982-6994 ◽  
Author(s):  
Jeffrey A. Mayfield ◽  
Béatrice Blanc ◽  
Kenton R. Rodgers ◽  
Gudrun S. Lukat-Rodgers ◽  
Jennifer L. DuBois
Keyword(s):  
Chlorite Dismutase

scholarly journals Spectral characterization of diarylpropane oxygenase, a novel peroxide-dependent, lignin-degrading heme enzyme.

1985 ◽  
Vol 260 (10) ◽  
pp. 6080-6087 ◽  
Author(s):  
L A Andersson ◽  
V Renganathan ◽  
A A Chiu ◽  
T M Loehr ◽  
M H Gold
Keyword(s):  
Spectral Characterization ◽  
Heme Enzyme

scholarly journals The Chlorite Dismutase (HemQ) fromStaphylococcus aureusHas a Redox-sensitive Heme and Is Associated with the Small Colony Variant Phenotype

2013 ◽  
Vol 288 (32) ◽  
pp. 23488-23504 ◽  
Author(s):  
Jeffrey A. Mayfield ◽  
Neal D. Hammer ◽  
Richard C. Kurker ◽  
Thomas K. Chen ◽  
Sunil Ojha ◽  
...  
Keyword(s):  
Chlorite Dismutase ◽  
Small Colony Variant ◽  
Variant Phenotype ◽  
Small Colony

Abstract 3490: Mechanistic Involvement of Myeloperoxidase in the Pathogenesis of Atrial Fibrillation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Volker Rudolph ◽  
Rene Andrie ◽  
Kai Friedrichs ◽  
Tanja K Rudolph ◽  
Anna Klinke ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ex Vivo ◽  
Strong Association ◽  
Neutrophil Activation ◽  
Right Atrial ◽  
Atrial Myocytes ◽  
Knock Out ◽  
Protein Residues ◽  
Heme Enzyme ◽  
Knock Out Mice

Background: Observational clinical and ex-vivo studies have established a strong association between atrial fibrillation (AF) and inflammation. However, whether inflammation is cause or consequence of AF and which specific inflammatory mediators increase atrial susceptibility to fibrillate remain elusive. Herein, we provide evidence for mechanistic involvement of myeloperoxidase (MPO), a heme enzyme abundantly expressed by neutrophils, in the pathophysiology of AF. Methods and Results: Patients with AF assessed by pacemaker interrogation not only exhibited higher circulating plasma levels of MPO (503.1 [IR:404.6 –880.7] vs. 437.8 [IR:348.9 – 488.0 pmol/l; p=0.03; n=42), they also revealed an increased MPO burden in explanted left atrial tissue as compared to patients devoid of AF. In AF-patients MPO co-localized with markedly increased formation of 3-nitro and 3-chlorotyrosin, protein oxidations known to be catalyzed by MPO. Myeloperoxidase knock-out mice, pretreated with angiotensin II infusion for 2 weeks yielding increased neutrophil activation, revealed strikingly attenuated vulnerability for AF during right atrial electrophysiological stimulation as compared to wild type mice (probability of AF-induction: 3.0 vs. 12.7%; p<0.01). Whereas the electrical homogeneity of the atrial myocytes was not altered between the groups, atria of MPO knock out mice were indicative of significantly reduced atrial fibrosis and markedly reduced formation of 3-chloro- and 3-nitrotyrosine. Conclusion: In conclusion, the current findings not only underscore the significance of neutrophil activation as a critical pathophysiological prerequisite of AF, but reveal that MPO - by oxidatively modifying protein residues and increasing fibrosis of atrial myocytes - is causally linked to the initiation and perpetuation of AF.

scholarly journals Structure and heme-binding properties of HemQ (chlorite dismutase-like protein) from Listeria monocytogenes

2015 ◽  
Vol 574 ◽  
pp. 36-48 ◽  
Author(s):  
Stefan Hofbauer ◽  
Andreas Hagmüller ◽  
Irene Schaffner ◽  
Georg Mlynek ◽  
Michael Krutzler ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Heme Binding ◽  
Binding Properties ◽  
Chlorite Dismutase
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