Crystal Structure of Fungal MagKatG2 at pH 5.5

Experimental Data Snapshot

  • Resolution: 1.40 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.151 
  • R-Value Observed: 0.152 

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Interaction with the Redox Cofactor MYW and Functional Role of a Mobile Arginine in Eukaryotic Catalase-Peroxidase.

Gasselhuber, B.Graf, M.M.Jakopitsch, C.Zamocky, M.Nicolussi, A.Furtmuller, P.G.Oostenbrink, C.Carpena, X.Obinger, C.

(2016) Biochemistry 55: 3528-3541

  • DOI: https://doi.org/10.1021/acs.biochem.6b00436
  • Primary Citation of Related Structures:  
    5JHX, 5JHY, 5JHZ

  • PubMed Abstract: 

    Catalase-peroxidases (KatGs) are unique bifunctional heme peroxidases with an additional posttranslationally formed redox-active Met-Tyr-Trp cofactor that is essential for catalase activity. On the basis of studies of bacterial KatGs, controversial mechanisms of hydrogen peroxide oxidation were proposed. The recent discovery of eukaryotic KatGs with differing pH optima of catalase activity now allows us to scrutinize those postulated reaction mechanisms. In our study, secreted KatG from the fungus Magnaporthe grisea (MagKatG2) was used to analyze the role of a remote KatG-typical mobile arginine that was shown to interact with the Met-Tyr-Trp adduct in a pH-dependent manner in bacterial KatGs. Here we present crystal structures of MagKatG2 at pH 3.0, 5.5, and 7.0 and investigate the mobility of Arg461 by molecular dynamics simulation. Data suggest that at pH ≥4.5 Arg461 mostly interacts with the deprotonated adduct Tyr. Elimination of Arg461 by mutation to Ala slightly increases the thermal stability but does not alter the active site architecture or the kinetics of cyanide binding. However, the variant Arg461Ala lost the wild-type-typical optimum of catalase activity at pH 5.25 (kcat = 6450 s(-1)) but exhibits a broad plateau between pH 4.5 and 7.5 (kcat = 270 s(-1) at pH 5.5). Moreover, significant differences in the kinetics of interconversion of redox intermediates of wild-type and mutant protein mixed with either peroxyacetic acid or hydrogen peroxide are observed. These findings together with published data from bacterial KatGs allow us to propose a role of Arg461 in the H2O2 oxidation reaction of KatG.

  • Organizational Affiliation

    Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Life Sciences , Muthgasse 18, A-1190 Vienna, Austria.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Catalase-peroxidase 2
A, B
764Pyricularia oryzae 70-15Mutation(s): 0 
Gene Names: KATG2CPXBMagKatG2MGG_09834
Find proteins for A4QUT2 (Magnaporthe oryzae (strain 70-15 / ATCC MYA-4617 / FGSC 8958))
Explore A4QUT2 
Go to UniProtKB:  A4QUT2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA4QUT2
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HEM

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C34 H32 Fe N4 O4
Experimental Data & Validation

Experimental Data

  • Resolution: 1.40 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.151 
  • R-Value Observed: 0.152 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 103.8α = 90
b = 109.72β = 90
c = 134.07γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-06-22
    Type: Initial release
  • Version 1.1: 2016-07-06
    Changes: Database references
  • Version 1.2: 2019-02-20
    Changes: Advisory, Data collection, Derived calculations