Role of the Oxyferrous Heme Intermediate and Distal Side Adduct Radical in the Catalase Activity of Mycobacterium Tuberculosis Katg Revealed by the W107F Mutant

Authors

Xiangbo Zhao, City University of New YorkFollow
Shengwei Yu, City University of New YorkFollow
Kalina Ranguelova, City University of New YorkFollow
Javier Suarez, City University of New YorkFollow
Leonid Metlitsky, City University of New YorkFollow
Johannes Schelvis, Montclair State UniversityFollow
Richard S. Magliozzo, City University of New YorkFollow

Document Type

Article

Publication Date

3-13-2009

Journal / Book Title

Journal of Biological Chemistry

Abstract

Catalase-peroxidase (KatG) is essential in Mycobacterium tuberculosis for oxidative stress management and activation of the antitubercular pro-drug isoniazid. The role of a unique distal side adduct found in KatG enzymes, involving linked side chains of residues Met255, Tyr229, and Trp107 (MYW), in the unusual catalase activity of KatG is addressed here and in our companion paper (Suarez, J., Ranguelova, K., Jarzecki, A. A., Manzerova, J., Krymov, V., Zhao, X., Yu, S., Metlitsky, L., Gerfen, G. J., and Magliozzo, R. S. (2009) J. Biol. Chem. 284, in press). The KatG[W107F] mutant exhibited severely reduced catalase activity yet normal peroxidase activity, and as isolated contains more abundant 6-coordinate heme in high spin and low spin forms compared with the wild-type enzyme. Most interestingly, oxyferrous heme is also found in the purified enzyme. Oxyferrous KatG[W107F] was prepared by photolysis in air of the carbonyl enzyme or was generated using hydrogen peroxide decayed with a t1/2 of 2 days compared with 6 min for wild-type protein. The stability of oxyenyzme was modestly enhanced in KatG[Y229F] but was not affected in KatG[M255A]. Optical stopped-flow experiments showed rapid formation of Compound I in KatG[W107F] and facile formation of oxyferrous heme in the presence of micromolar hydrogen peroxide. An analysis of the relationships between catalase activity, stability of oxyferrous enzyme, and a proposed MYW adduct radical is presented. The loss of catalase function is assigned to the loss of the MYW adduct radical and structural changes that lead to greatly enhanced stability of oxyenzyme, an intermediate of the catalase cycle of native enzyme.

Comments

This article is Open Access and distributed under a Creative Commons 4.0 license.

DOI

10.1074/jbc.M808107200

Montclair State University Digital Commons Citation

Zhao, Xiangbo; Yu, Shengwei; Ranguelova, Kalina; Suarez, Javier; Metlitsky, Leonid; Schelvis, Johannes; and Magliozzo, Richard S., "Role of the Oxyferrous Heme Intermediate and Distal Side Adduct Radical in the Catalase Activity of Mycobacterium Tuberculosis Katg Revealed by the W107F Mutant" (2009). Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works. 86.
https://digitalcommons.montclair.edu/chem-biochem-facpubs/86