role for Haemophilus ducreyi Cu,ZnSOD in resistance to heme toxicity

• Published in: Biometals Vol. 21; no. 3; pp. 249 - 258
• Main Authors: Negari, Shahin, Sulpher, Jeff, Pacello, Francesca, Ingrey, Keely, Battistoni, Andrea, Lee, B. Craig
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.06.2008; Springer Netherlands; Springer Nature B.V
• Subjects: Biochemistry; Biomedical and Life Sciences; Cell Biology; Cu,ZnSOD; Enzymes; Genetic Complementation Test; Haemophilus ducreyi; Haemophilus ducreyi - cytology; Haemophilus ducreyi - drug effects; Haemophilus ducreyi - enzymology; Haemophilus ducreyi - genetics; heme; Heme - toxicity; Inactivation; Iron; Life Sciences; Medicine/Public Health; Microbial Viability - drug effects; Microbiology; Mutants; Mutation - genetics; Pharmacology/Toxicology; Plant Physiology; superoxide dismutase; Superoxide Dismutase - metabolism; Toxicity; Superoxide dismutase; Cu,ZnSOD; Heme
• ISSN: 0966-0844; 1572-8773
• DOI: 10.1007/s10534-007-9113-8

The Cu,Zn superoxide dismutase (Cu,ZnSOD) from Haemophilus ducreyi is the only enzyme of this class which binds a heme molecule at its dimer interface. To explore the role of the enzyme in this heme-obligate bacterium, a sodC mutant was created by insertional inactivation. No difference in growth rate was observed during heme limitation. In contrast, under heme rich conditions growth of the sodC mutant was impaired compared to the wild type strain. This growth defect was abolished by supplementation of exogenous catalase. Genetic complementation of the sodC mutant in trans demonstrated that the enzymatic property or the heme-binding activity of the protein could repair the growth defect of the sodC mutant. These results indicate that Cu,ZnSOD protects Haemophilus ducreyi from heme toxicity.