A role for Haemophilus ducreyi Cu,ZnSOD in resistance to heme toxicity.
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.
Negari
Shahin
S
Department of Biochemistry Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada, K1H 8M5.
Sulpher
Jeff
J
Pacello
Francesca
F
Ingrey
Keely
K
Battistoni
Andrea
A
Lee
B Craig
BC
D005816:Genetic Complementation Test; D006191:Haemophilus ducreyi / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D006418:Heme / Q000633:toxicity*; D050296:Microbial Viability / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D013482:Superoxide Dismutase / Q000378:metabolism*
D006418:Heme; D013482:Superoxide Dismutase