[Role of dpr in hydrogen peroxide tolerance of Streptococcus oligofermentans].
OBJECTIVE
Streptococcus oligofermentans was a newly characterized streptococcal species, which we isolated from dental plaques of carious-free humans. Our previous work indicated that in aerobic environments, it produced, as well as survived high concentration of hydrogen peroxide (4.4 mmol/L). This study analyzed the function of dpr gene in hydrogen peroxide tolerance of Streptococcus oligofermentans.


METHODS
Cloned and expressed the dpr gene, and characterized Dpr protein. We constructed the dpr mutant strain of S. oligfermentans and detected its susceptivity to hydrogen peroxide. Furthermore, S. oligofermentans dpr gene was cloned into S. mutans, and its susceptivity to hydrogen peroxide was tested.


RESULTS
S. oligofermentans dpr mutant strain was much more susceptive to hydrogen peroxide than the wild type, and introduction of its dpr gene into S. mutans could enhance the later' s hydrogen peroxide tolerant ability. Dpr proteins could bind irons, but not to DNA. [Conclusion] dpr gene of S. oligofermentans has significant role in hydrogen peroxide tolerance of the host strain, while Dpr protein may have other oxidant-damage protective mechanisms except for iron-binding.
Zhu
Baoli
B
Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China. baolizhu@gmail.com
Tong
Huichun
H
Chen
Wei
W
Dong
Xiuzhu
X
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000378:metabolism*; D013291:Streptococcus / Q000235:genetics / Q000378:metabolism*; D013295:Streptococcus mutans / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C414750:Dpr protein, Streptococcus; D006861:Hydrogen Peroxide