RadA:A protein involved in DNA damage repair processes of Deinococcus radiodurans R1  

作　　者：ZHOU Qing ZHANG Xinjue XU Hong XU Bujin HUA Yuejin 

机构地区：[1]Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou 310029, China

出　　处：《Chinese Science Bulletin》2006年第24期2993-2999,共7页

基　　金：Acknowledgements The authors would like to thank Prof. Fu Junjie （Radiation Center of Zhejiang University） for his help in irradiation treatment. This work was supported by the National Basic Research Program of China （Grant No. 2004CB19604）, a grant for Distinguished Young Scientist of China （Grant No. 30425038） and the National Natural Science Foundation of China （Grant No. 30330020）.

摘　　要：RadA is highly conserved in bacteria and belongs to the RecA/RadA/Rad51 protein su-perfamily found in bacteria,archaea and eukarya. In Archaea,it plays a critical role in homologous re-combination process due to its RecA-like function. In Escherichia coli,it takes part in conjugational recom-bination and DNA repair but is not as important as that of archaea. Using PSI-BLAST searches,we found that Deinococcus radiodurans RadA had a higher similarity to that of bacteria than archaea and eukarya. Disruption of radA gene in D. radiodurans resulted in a modestly decreased resistance to gamma radiation and ultraviolet,but had no effect on the resistance to hydrogen peroxide. Complementa-tion of the radA disruptant by both E. coli radA and D. radiodurans radA could fully restore its resistance to gamma radiation and ultraviolet irradiation. Further domain function analyses of D. radiodurans RadA showed that the absence of the zinc finger domain resulted in a slightly more sensitive phenotype to gamma and UV radiation than that of the radA mutant,while the absence of the Lon protease domain exhib-ited a slightly increased resistance to gamma and UV radiation. These data suggest that D. radiodurans RadA does play an important role in the DNA damage repair processes and its three different domains have different functions.RadA is highly conserved in bacteria and belongs to the RecNRadNRad51 protein superfamily found in bacteria, archaea and eukarya. In Archaea, it plays a critical role in homologous recombination process due to its RecA-like function. In Escherichia coli, it takes part in conjugational recombination and DNA repair but is not as important as that of archaea. Using PSI-BLAST searches, we found that Deinococcus radiodurans RadA had a higher similarity to that of bacteria than archaea and eukarya. Disruption of radA gene in D. radiodurans resulted in a modestly decreased resistance to gamma radiation and ultraviolet, but had no effect on the resistance to hydrogen peroxide. Complementation of the radA disruptant by both E. coil radA and D. radiodurans radA could fully restore its resistance to gamma radiation and ultraviolet irradiation. Further domain function analyses of D. radiodurans RadA showed that the absence of the zinc finger domain resulted in a slightly more sensitive phenotype to gamma and UV radiation than that of the radA mutant while the absence of the Lon protease domain exhibited a slightly increased resistance to gamma and UV radiation. These data suggest that D. radiodurans RadA does play an important role in the DNA damage repair processes and its three different domains have different functions.

关 键 词：DNA损伤修复 RadA蛋白 细菌 同源重组 

分 类 号：Q51[生物学—生物化学] Q754