| Title |
Iso-Superoxide Dismutase in Deinococcus grandis, a UV Resistant Bacterium |
| Author |
Na-Rae Yun and Young Nam Lee* |
| Address |
Department of Microbiology, Chungbuk National University, Cheongju 361-763, Republic of Korea |
| Bibliography |
Journal of Microbiology, 47(2),172-177, 2009,
|
| DOI |
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| Key Words |
Deinococcus grandis, iso-SODs, membrane bound SOD, inducible cytosolic SOD |
| Abstract |
Deinococcus grandis possesses two types of superoxide dismutase (SOD, E. C. 1.15.1.1.) that show distinct electrophoretic behavior, one that migrates slowly and the other that migrates rapidly (SOD-1 and SOD-2, respectively). In this study, SOD-1 was uniformly and abundantly detected, regardless of growth phase, whereas SOD-2 was not detected during early growth, but was detectable from the exponential growth phase. In addition, a substantial increase in SOD-2 was observed in cells that were treated with potassium superoxide or UV, which suggests that SOD-2 is an inducible protein produced in response to stressful environments. Insensitivity of SOD-1 to both H2O2 and cyanide treatment suggests that SOD-1 is MnSOD. However, SOD-2 would be FeSOD, since it lost activity in response to H2O2 treatment, but not to cyanide. Localization studies of D. grandis iso-SODs in sucrose-shocked cells suggest that SOD-1 is a membrane-associated enzyme, whereas SOD-2 is a cytosolic enzyme. In conclusion, SOD-1 seems to be an essential constitutive enzyme for viability and SOD-2 appears to be an inducible enzyme that is probably critical for survival upon UV irradiation and oxidative stress. |
