Iso-superoxide dismutase in Deinococcus grandis, a UV resistant bacterium.
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 H(2)O(2) and cyanide treatment suggests that SOD-1 is MnSOD. However, SOD-2 would be FeSOD, since it lost activity in response to H(2)O(2) 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.
Yun
Na-Rae
NR
Department of Microbiology, Chungbuk National University, Cheongju, 361-763, Republic of Korea.
Lee
Young Nam
YN
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034301:Deinococcus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects*; D004795:Enzyme Stability; D015971:Gene Expression Regulation, Enzymologic; D021381:Protein Transport; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D013482:Superoxide Dismutase