Uversky V N, Kutyshenko V P, Rogov V V, Vassilenko K S, Gudkov A T
Institute of Protein Research, Russian Academy of Sciences, Moscow Region, Russia.
Protein Sci. 1996 Sep;5(9):1844-51. doi: 10.1002/pro.5560050910.
It is obvious that functional activity of a protein molecule is closely related to its structure. On the other hand, the understanding of structure-function relationship still remains one of the intriguing problems of molecular biology. There is widespread belief that mutagenesis presents a real way to solve this problem. Following this assumption, we have investigated the effect of circular permutation in dihydrofolate reductase from E. coli on protein structure and functioning. It has been shown that in the absence of ligands two circularly permuted variants of dihydrofolate reductase possess all the properties of the molten globule state. However, after addition of ligands they gain the native-like structural properties and specific activity. This means that the in vitro folding of permuted dihydrofolate reductase is terminated at the stage of the molten globule formation. Interaction of permuted protein with ligands leads to the structural adjustment and formation of active protein molecules.
很明显，蛋白质分子的功能活性与其结构密切相关。另一方面，对结构-功能关系的理解仍然是分子生物学中一个引人入胜的问题。人们普遍认为，诱变是解决这个问题的一种切实可行的方法。基于这一假设，我们研究了大肠杆菌二氢叶酸还原酶中的环形排列对蛋白质结构和功能的影响。结果表明，在没有配体的情况下，二氢叶酸还原酶的两种环形排列变体具有熔球态的所有特性。然而，添加配体后，它们获得了类似天然的结构特性和比活性。这意味着，排列后的二氢叶酸还原酶的体外折叠在熔球形成阶段终止。排列后的蛋白质与配体的相互作用导致结构调整并形成活性蛋白质分子。
