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Gewählte Publikation:

Zamocky, M; Kamlarova, A; Maresch, D; Chovanova, K; Harichova, J; Furtmuller, PG.
(2020): Hybrid Heme Peroxidases from Rice Blast FungusMagnaporthe oryzaeInvolved in Defence against Oxidative Stress
ANTIOXIDANTS-BASEL. 2020; 9(8), 655 FullText FullText_BOKU

Hybrid B heme peroxidases are recently discovered unique oxidoreductases present solely in the fungal kingdom. We have investigated two typical representatives fromMagnaporthe oryzae-one of the most dangerous phytopathogens known as a causal agent of the rice blast disease. First, we focused on native expression of two detectedhyBpoxparalogs by the means of reverse-transcription quantitative real-time PCR. Our results indicate a 7-fold induction of theMohyBpox1transcript in a medium with H(2)O(2)and a 3-fold induction in a medium with peroxyacetic acid. For theMohyBpox2paralog the induction patterns were up to 12-fold and 6.7-fold, respectively. We have successfully expressed the shorter gene,MohyBpox1, heterologously inPichia pastorisfor detailed characterization. Observed biochemical and biophysical properties of the highly purified protein reveal that a typical HyBPOX is significantly different from previously investigated APx-CcP hybrids. This newly discovered secretory peroxidase reveals a Soret maximum at 407 nm, Q bands at 532 and 568 nm, CT band at 625 nm and a purity number of 1.48. Electron paramagnetic resonance (EPR) analysis suggests a mixture of high and low spin species in the ferric state dependent on calcium contents. Steady-state kinetic data reveal the highest peroxidase activity with ABTS, 5-aminosalycilate and efficient oxidation of tyrosine. MoHyBPOX1 as a fusion protein consists of two domains. The longer conserved N-terminal peroxidase domain is connected with a shorter C-terminal domain containing a carbohydrate binding motif of type CBM21. We demonstrate the capacity of MoHyBPOX1 to bind soluble starch efficiently. Potential involvement of hybrid peroxidases in the pathogenicity ofM. oryzaeis discussed.
Autor*innen der BOKU Wien:
Furtmüller Paul Georg
Zamocky Marcel

Find related publications in this database (Keywords)
oxidative stress
peroxidase-catalase superfamily
Magnaporthe oryzae
hybrid B heme peroxidase
carbohydrate binding domain

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