Heme binding and peroxidase activity of a secreted minicatalase. Issue 24 (28th November 2016)

• Record Type: Journal Article
• Authors: Mori, Giulia; Doniselli, Nicola; Faroldi, Federica; Percudani, Riccardo
• Is Part Of: FEBS letters. Volume 590:Issue 24(2016)
• Page Start: 4495
• Page End: 4506
• Publication Date: 2016-11-28
• Subjects: disulfide bond -- heme binding -- host–pathogen interaction -- hydrogen peroxide -- oxidative stress -- periplasmic protein; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1002/1873-3468.12493
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : Microbial pathogens often require efficient and robust H2 O2 scavenger activities to survive in the presence of reactive oxygen species generated by inflammatory responses. In addition to catalases and peroxidases, enzymes known to scavenge H2 O2, a novel class of secreted minicatalases is found in diderm bacteria. Here, we characterize the Helicobacter pylori ( Hp ) minicatalase: a monomeric hemoprotein with catalase core homology. Overexpression of Hp minicatalase rescued a catalase/peroxidase‐deficient Escherichia coli phenotype under aerobic conditions and limited H2 O2 stress. The purified enzyme lacks catalase activity, but has strong ( k cat > 100 s −1 ) H2 O2 ‐dependent peroxidase activity toward a variety of organic substrates. Our investigations into heme binding revealed that the heme cofactor is assembled in the periplasm to form the functional holoprotein. Furthermore, we observed the presence of a disulfide bond near the heme cavity of Hp minicatalase, which is conserved in secreted minicatalases and, therefore, may play a role in heme binding. Abstract :