State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
Int J Biol Macromol. 2010 Oct 1;47(3):366-70. doi: 10.1016/j.ijbiomac.2010.06.001. Epub 2010 Jun 15.
Species-specific protein thermal stability is closely correlated to the living conditions of the organism, especially to its body temperature. In this research, human and zebrafish muscle-type creatine kinases (MMCKs) were taken as model proteins to investigate the molecular adaptation of proteins in poikilothermal and homoiothermal animals. Both the optimal temperature for catalysis and the thermal stability of human MMCK was much higher than those of zebrafish MMCK. Sequence alignment identified 9 amino acid variations conserved in either the teleost MMCKs or the mammal and electric ray MMCKs. Bidirectional mutations were performed to find the residues with beneficial mutations. The results showed that two residues close to the dimer interface of MMCK, the 46th and 146th residue, were crucial for species-specific thermal stability.
种属特异性蛋白质热稳定性与生物体的生活条件密切相关，尤其是与体温相关。在这项研究中，我们以人类和斑马鱼肌肉型肌酸激酶（MMCK）作为模型蛋白，研究变温动物和恒温动物中蛋白质的分子适应。人类 MMCK 的最适催化温度和热稳定性均明显高于斑马鱼 MMCK。序列比对确定了在硬骨鱼类 MMCK 或哺乳动物和电鳐 MMCK 中保守的 9 个氨基酸变异。双向突变以寻找具有有利突变的残基。结果表明，MMCK 二聚体界面附近的两个残基（第 46 位和第 146 位）对于种属特异性热稳定性至关重要。
