Selected Publication:

Zámocký, M; Droghetti, E; Bellei, M; Gasselhuber, B; Pabst, M; Furtmüller, PG; Battistuzzi, G; Smulevich, G; Obinger, C; .
(2012): Eukaryotic extracellular catalase-peroxidase from Magnaporthe grisea - Biophysical/chemical characterization of the first representative from a novel phytopathogenic KatG group.
Biochimie. 2012; 94(3):673-683 FullText FullText_BOKU

Abstract:

All phytopathogenic fungi have two catalase peroxidase paralogues located either intracellularly (KatG1) or extracellularly (KatG2). Here, for the first time a secreted bifunctional, homodimeric catalase-peroxidase (KatG2 from the rice blast fungus Magnaporthe grisea) has been produced heterologously with almost 100% heme occupancy and comprehensively investigated by using a broad set of methods including UV-Vis, ECD and resonance Raman spectroscopy (RR), thin-layer spectroelectrochemistry, mass spectrometry, steady-state & presteady-state spectroscopy. RR spectroscopy reveals that MagKatG2 shows a unique mixed-spin state, non-planar heme b, and a proximal histidine with pronounced imidazolate character. At pH 7.0 and 25 degrees C, the standard reduction potential E degrees' of the Fe(III)/Fe(II) couple for the high-spin native protein was found to fall in the range typical for the KatG family. Binding of cyanide was relatively slow at pH 7.0 and 25 degrees C and with a K-d value significantly higher than for the intracellular counterpart. Demonstrated by mass spectrometry MagKatG2 has the typical Trp118-Tyr251-Met277 adduct that is essential for its predominantly catalase activity at the unique acidic pH optimum. In addition, MagKatG2 acts as a versatile peroxidase using both one- and two-electron donors. Based on these data, structure function relationships of extracellular eukaryotic KatGs are discussed with respect to intracellular KatGs and possible role(s) in host pathogen interaction. (C) 2011 Elsevier Masson SAS. All rights reserved.

Authors BOKU Wien:

Furtmüller Paul Georg

Gasselhuber Bernhard

Obinger Christian

Zamocky Marcel

Find related publications in this database (using NML MeSH Indexing)

Catalase/chemistry*;Catalase/classification;Catalase/metabolism*;Fungal Proteins/chemistry;Fungal Proteins/metabolism;Magnaporthe/enzymology*;Magnaporthe/metabolism;Oxidative Stress;Peroxidases/chemistry*;Peroxidases/classification;Peroxidases/metabolism*;Phylogeny;Spectrum Analysis, Raman;

Find related publications in this database (Keywords)

Extracellular catalase-peroxidase

Peroxidases-catalase superfamily

Phytopathogen

Oxidative stress

Resonance Raman spectroscopy

Reduction potential

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