Jeong J H, Kwon E S, Roe J H
Laboratory of Molecular Microbiology, Seoul National University, Seoul, 151-742, Korea.
Biochem Biophys Res Commun. 2001 May 18;283(4):908-14. doi: 10.1006/bbrc.2001.4853.
Fission yeast Schizosaccharomyces pombe contains two superoxide dismutases (SODs), one in the cytosol and the other in mitochondria. The sod2+ gene encoding putative mitochondrial superoxide dismutase containing manganese (MnSOD) has been isolated. Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. It was localized in mitochondria as expected. Its N-terminal amino acid sequence indicated that the mitochondrial targeting sequence of 21 amino acids was removed. The native form consisted of two identical subunits. The sod2+ expression was induced by external stresses, such as treatments with superoxide generators, high osmolarity, and heat. The induction by these stress treatments depended on Wis1-Spc1 MAPK signal transduction pathway being independent of transcription factors Atf1 or Pap1. The sod2 disruption rendered cells sensitive to various superoxide-generators, heat, and high osmolarity, suggesting that the mitochondrial MnSOD acts as a general defense agent against multiple stresses.
裂殖酵母粟酒裂殖酵母含有两种超氧化物歧化酶（SOD），一种存在于细胞质中，另一种存在于线粒体中。编码假定的含锰线粒体超氧化物歧化酶（MnSOD）的sod2+基因已被分离出来。对sod2+基因产物的纯化和分析表明，它仅含有锰作为辅因子，因此被证实是一种真正的MnSOD。正如预期的那样，它定位于线粒体中。其N端氨基酸序列表明，21个氨基酸的线粒体靶向序列被去除。天然形式由两个相同的亚基组成。sod2+的表达受到外部应激的诱导，如用超氧化物发生器处理、高渗透压和热刺激。这些应激处理的诱导依赖于Wis1-Spc1 MAPK信号转导途径，独立于转录因子Atf1或Pap1。sod2基因的破坏使细胞对各种超氧化物发生器、热和高渗透压敏感，这表明线粒体MnSOD作为一种针对多种应激的通用防御因子发挥作用。
