Liu Jiao, Tang Xuexi, Wang You, Zang Yu, Zhou Bin
College of Marine Life Science, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
College of Marine Life Science, Ocean University of China, 5 Yushan Road, Qingdao 266003, China.
Gene. 2016 Jan 10;575(2 Pt 3):718-24. doi: 10.1016/j.gene.2015.09.050. Epub 2015 Sep 26.
Superoxide dismutase (SOD) is an essential enzyme playing a pivotal role in the protection mechanism against oxidative stress by reducing superoxide radicals. In the present study, the full-length cDNA sequence of manganese superoxide dismutase was identified from Zostera marina (ZmMnSOD) via raid amplification of cDNA ends (RACE) technique and expressed sequence tags (ESTs) analysis. The open reading frame (ORF) encoded a polypeptide of 254 amino acid residues, which shared 69%-77% similarity with previous identified SODs. Analysis of the deduced amino acid revealed conserved features, including functional domains, signature motifs and metal binding sites. Phylogenetic analysis revealed that ZmMnSOD was closer to the SODs from angiosperm than those from other organisms. The mRNA expression level of ZmMnSOD at different temperatures was investigated using real-time PCR and it was significantly up-regulated from 5°C to 15°C, and then dramatically down-regulated. The recombinant ZmMnSOD protein was purified and exhibited Mn(2+) ions dependency specific enzymatic activity and strong antioxidant activity over a wide temperature range. All these results indicate that ZmMnSOD is an authentic member of the plant SOD family and may play important roles in minimizing the effect of oxidative damage in Z. marina against temperature stress and affect the adaptability of Z. marina to global warming.
超氧化物歧化酶（SOD）是一种重要的酶，通过还原超氧自由基在抗氧化应激保护机制中发挥关键作用。在本研究中，通过cDNA末端快速扩增（RACE）技术和表达序列标签（ESTs）分析，从滨海大叶藻（ZmMnSOD）中鉴定出锰超氧化物歧化酶的全长cDNA序列。开放阅读框（ORF）编码一个由254个氨基酸残基组成的多肽，与先前鉴定的SOD具有69%-77%的相似性。对推导的氨基酸分析揭示了保守特征，包括功能域、特征基序和金属结合位点。系统发育分析表明，ZmMnSOD与被子植物的SOD比与其他生物的SOD更接近。使用实时PCR研究了ZmMnSOD在不同温度下的mRNA表达水平，其在5°C至15°C时显著上调，然后急剧下调。重组ZmMnSOD蛋白被纯化，并在较宽温度范围内表现出对Mn(2+)离子依赖性的特定酶活性和强抗氧化活性。所有这些结果表明，ZmMnSOD是植物SOD家族的一个真正成员，可能在最小化滨海大叶藻中氧化损伤对温度胁迫的影响以及影响滨海大叶藻对全球变暖的适应性方面发挥重要作用。
