Biochemical Characterization of Psychrophilic Mn-Superoxide Dismutase from Newly Isolated Exiguobacterium sp. OS-77
Biochemical Characterization of Psychrophilic Mn-Superoxide Dismutase from Newly Isolated Exiguobacterium sp. OS-77
复制标题
新分离的微小杆菌属嗜冷锰超氧化物歧化酶的生化特征。
DOI：
10.1007/s00792-013-0621-x
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发表时间：
2014
期刊：
影响因子：
2.9
通讯作者：
Seiji
中科院分区：
文献类型：
--
作者：
Nonaka;Kyoshiro; Yoon;Ki-Seok; Ogo;Seiji
许多类型的超氧化物歧化酶已从各种细菌中纯化和表征，然而，嗜冷锰超氧化物歧化酶（MnSOD）尚未报道。在这里，我们描述了嗜冷MnSOD的纯化和生化特性的嗜冷细菌。菌株OS-77（EgMnSOD）。根据16 SrRNA序列分析，新分离到一株细菌OS-77，属于古细菌属。菌株OS-77的最适生长温度为20 ℃。经SDS-PAGE和凝胶过滤分析，EgMnSOD是23.5kDa多肽的同源二聚体。UV-Vis光谱和ICP-MS分析清楚地表明，均匀纯化的酶仅含有作为金属辅因子的Mn离子。该酶的最适反应pH为9.0，最适反应温度为5 °C。值得注意的是，纯化的EgMnSOD在高达45 °C下是热稳定的，并且在60 °C下21.2分钟后保留50%的活性。差示扫描量热法也表明EgMnSOD是热稳定的，在65和84 °C有两个蛋白质变性峰。对EgMnSOD的氨基酸序列和组成的统计分析表明，该酶具有嗜冷性。
Many types of superoxide dismutases have been purified and characterized from various bacteria, however, a psychrophilic Mn-superoxide dismutase (MnSOD) has not yet been reported. Here, we describe the purification and the biochemical characterization of the psychrophilic MnSOD fromExiguobacteriumsp. strain OS-77 (EgMnSOD). According to 16S rRNA sequence analysis, a newly isolated bacterium strain OS-77 belongs to the genusExiguobacterium. The optimum growth temperature of the strain OS-77 is 20 °C. TheEgMnSOD is a homodimer of 23.5 kDa polypeptides determined by SDS-PAGE and gel filtration analysis. UV-Vis spectrum and ICP-MS analysis clearly indicated that the homogeneously purified enzyme contains only a Mn ion as a metal cofactor. The optimal reaction pH and temperature of the enzyme were pH 9.0 and 5 °C, respectively. Notably, the purifiedEgMnSOD was thermostable up to 45 °C and retained 50 % activity after 21.2 min at 60 °C. The differential scanning calorimetry also indicated that theEgMnSOD is thermostable, exhibiting two protein denaturation peaks at 65 and 84 °C. The statistical analysis of amino acid sequence and composition of theEgMnSOD suggests that the enzyme retains psychrophilic characteristics.