【作者】 李国亭； 赵亚琴； 王志军； 任列香； 杨斌盛；

【Author】 Guo-Ting Li, Ya-Qin Zhao, Zhi-Jun Wang, Lie-Xiang Ren, Bin-Sheng Yang * Institute of Molecular Science, Chemical Biology and Molecular Engineering Laboratory of Education Ministry, Shanxi University, 030006,Taiyuan

【机构】 山西大学分子科学研究所,化学生物学与分子工程教育部重点实验室；

【Abstract】 Euplotes octocarinatus centrin (EoCen) is a small size (～20kDa) calcium binding protein belonging to the EF-hand protein superfamily. The first amino acid of the E-helix of the EF-hand protein is highly conserved as Glu. In this paper, Glu101, the first amino acid of the E-helix of the third EF-hand motif in EoCen was changed to Lys by the method of site direct mutation for the first time. The experiments of the binding of proteins to hydrophobic probe TNS and Tb3+ energy transfer were done and the results indicate that compared with EoCen, the mutation protein produces a different Tb3+ binding characteristic and an increased hydrophobic exposure surface. It proves that the conformation of EoCen has been altered by this mutation. The general binding constant of the loops of EF-hand sites I, II, III in the mutation protein was calculated to be (5.64 ± 0.57) × 105 M-1 according to the modified equation of the single binding process.更多还原