Haikarainen Teemu, Frioux Clémence, Zhnag Li-Qing, Li Duo-Chuan, Papageorgiou Anastassios C
Turku Centre for Biotechnology, University of Turku, BioCity, Turku 20521, Finland; Åbo Akademi University, BioCity, Turku 20521, Finland.
Department of Environmental Biology, Shandong Agricultural University, Taian, Shandong 271018, China; Department of Chemistry and Chemical Engineering, Taishan Medical College, Taian, Shandong 271016, China.
Biochim Biophys Acta. 2014 Feb;1844(2):422-9. doi: 10.1016/j.bbapap.2013.11.014. Epub 2013 Dec 3.
A manganese superoxide dismutase from the thermophilic fungus Chaetomium thermophilum (CtMnSOD) was expressed in Pichia pastoris and purified to homogeneity. Its optimal temperature was 60°C with approximately 75% of its activity retained after incubation at 70°C for 60min. Recombinant yeast cells carrying C. thermophilum mnsod gene exhibited higher stress resistance to salt and oxidative stress-inducing agents than control yeast cells. In an effort to provide structural insights, CtMnSOD was crystallized and its structure was determined at 2.0Å resolution. The overall architecture of CtMnSOD was found similar to other MnSODs with highest structural similarities obtained against a MnSOD from the thermotolerant fungus Aspergillus fumigatus. In order to explain its thermostability, structural and sequence analysis of CtMnSOD with other MnSODs was carried out. An increased number of charged residues and an increase in the number of intersubunit salt bridges and the Thr:Ser ratio were identified as potential reasons for the thermostability of CtMnSOD.
来自嗜热真菌嗜热毛壳菌（CtMnSOD）的锰超氧化物歧化酶在毕赤酵母中表达并纯化至同质。其最适温度为60°C，在70°C孵育60分钟后仍保留约75%的活性。携带嗜热毛壳菌mnsod基因的重组酵母细胞比对照酵母细胞对盐和氧化应激诱导剂表现出更高的抗逆性。为了提供结构见解，CtMnSOD被结晶，并以2.0Å的分辨率确定了其结构。发现CtMnSOD的整体结构与其他MnSOD相似，与耐热真菌烟曲霉的MnSOD结构相似性最高。为了解释其热稳定性，对CtMnSOD与其他MnSOD进行了结构和序列分析。带电残基数量的增加、亚基间盐桥数量的增加以及苏氨酸：丝氨酸比例的增加被确定为CtMnSOD热稳定性的潜在原因。
