An iron-binding protein, Dpr, decreases hydrogen peroxide stress and protects Streptococcus pyogenes against multiple stresses.
Streptococcus pyogenes does not produce catalase, but it can grow in aerobic environments and survive in the presence of peroxide. One of the stress proteins of this organism, peroxide resistance protein (Dpr), has been studied to examine its role in resistance to hydrogen peroxide, but the protective mechanism of Dpr is not clear. The aim of this study was to characterize the dpr gene and its role in dealing with different stresses. A dpr deletion mutant was constructed by double-crossover mutagenesis. The dpr mutant was more sensitive to H(2)O(2), and complementation could partially restore the defect in the mutant. Pretreatment with the iron chelator deferoxamine mesylate rescued the survival activity of the mutant under oxidative stress conditions. The dpr mutant also showed a low survival rate in the long-term stationary phase, when it was treated with extreme acids, and under alkaline pH conditions compared to the wild-type strain. The growth of the dpr mutant was slower than that of the wild-type strain in iron-limiting conditions. The dpr mutant showed high sensitivity to iron and zinc but not to manganese, copper, nickel, and calcium. Recombinant Dpr protein was purified and showed iron-binding activity, whereas no DNA-binding activity was found. These data indicate that an iron-binding protein, Dpr, provides protection from hydrogen peroxide stress by preventing the Fenton reaction, and Dpr was identified as a novel stress protein that protects against several stresses in group A streptococci.
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Chih-Cheng
CC
Tsou
Chuan
C
Chiang-Ni
Yee-Shin
YS
Lin
Woei-Jer
WJ
Chuang
Ming-T
MT
Lin
Ching-Chuan
CC
Liu
Jiunn-Jong
JJ
Wu
D000143:Acids / Q000633:toxicity; D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000633:toxicity*; D033862:Iron-Binding Proteins / Q000502:physiology*; D008670:Metals / Q000378:metabolism; D050296:Microbial Viability; D016254:Mutagenesis, Insertional; D018384:Oxidative Stress; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000235:genetics / Q000502:physiology*
D000143:Acids; D001426:Bacterial Proteins; D003470:Culture Media; D004268:DNA-Binding Proteins; C414750:Dpr protein, Streptococcus; D033862:Iron-Binding Proteins; D008670:Metals; D006861:Hydrogen Peroxide