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为研究南极鱼类HSP90β蛋白与低温适应的相关性,本研究克隆获得了南极独角雪冰鱼(Chionodraco hamatus,CH)热休克蛋白HSP90β基因的完整开放阅读框,并以尼罗罗非鱼(Oreochromis niloticus,ON)HSP90β蛋白为对照,进行低温胁迫下的原核表达研究。结果表明:克隆获得的独角雪冰鱼HSP90β基因编码区全长为2 184 bp,推定编码728个氨基酸。多重序列比对显示,独角雪冰鱼HSP90β与其他鱼类HSP90β的氨基酸序列同源性在87%以上;蛋白结构域分析发现,独角雪冰鱼HSP90β具有HSP90家族的保守信号区,其重要功能位点的氨基酸残基非常保守。构建pE T28-CH-HSP90β和pE T28-ON-HSP90β重组表达载体,观察4℃低温胁迫8 h和12 h后,HSP90β蛋白对大肠杆菌生存能力的影响。结果显示:C.hamatus-HSP90β组的大肠杆菌存活率显著高于O.niloticus-HSP90β组和空载体pE T28a对照组,这表明南极冰鱼HSP90β在低温条件下具有更加显著的细胞保护功能。由此推测HSP90β蛋白参与了南极冰鱼低温适应的生理过程。
In order to study the correlation between the HSP90β protein and the adaptation to low temperature in Antarctic fish, we cloned the complete open reading frame of the heat shock protein HSP90β gene of Chionodraco hamatus (CH) Oreochromis niloticus ON) HSP90βprotein was used as a control for prokaryotic expression under low temperature stress. The results showed that the full-length coding region of HSP90β gene cloned was 2 184 bp and deduced 728 amino acids. Multiple sequence alignment showed that the amino acid sequence homology of HSP90β with other fish HSP90β was above 87%. Protein domain analysis showed that HSP90β had a conserved signal region of HSP90 family Amino acid residues at functional sites are very conserved. The recombinant expression vectors pE T28-CH-HSP90β and pE T28-ON-HSP90β were constructed and the effects of HSP90β protein on the viability of E.coli were observed at 8 and 12 h after 4 ℃ cold stress. The results showed that the survival rate of E. coli in C.hamatus-HSP90β group was significantly higher than that of O.niloticus-HSP90βgroup and empty vector pE T28a control group, indicating that Antarctic ice-fish HSP90β had more significant cytoprotection under low temperature conditions. It was speculated that HSP90β protein involved in the adaptation of the Antarctic icefish physiological processes.