White M F, Fothergill-Gilmore L A, Kelly S M, Price N C
Department of Biochemistry, University of Edinburgh, U.K.
Biochem J. 1993 Apr 15;291 ( Pt 2)(Pt 2):479-83. doi: 10.1042/bj2910479.
The structure and stability of a mutated yeast phosphoglycerate mutase in which His-181 has been replaced by alanine have been studied. The secondary, tertiary and quaternary structures of the mutant enzyme in the absence of ligands are essentially identical to those of the wild-type enzyme as revealed by c.d., fluorescence and cross-linking studies. The mutant enzyme is slightly less stable than the wild-type enzyme towards denaturation by guanidium chloride (GdnHCl). On addition of cofactor 2,3-bisphosphoglycerate, the wild-type enzyme shows increased stability towards GdnHCl. However, addition of cofactor causes dramatic changes in the structure of the mutant enzyme, leading to dissociation of the tetrameric form to dimeric and monomeric species.
对组氨酸-181被丙氨酸取代的突变型酵母磷酸甘油酸变位酶的结构和稳定性进行了研究。通过圆二色性（c.d.）、荧光和交联研究表明，在没有配体的情况下，突变酶的二级、三级和四级结构与野生型酶基本相同。突变酶对氯化胍（GdnHCl）变性的稳定性略低于野生型酶。加入辅因子2,3-二磷酸甘油酸后，野生型酶对GdnHCl的稳定性增加。然而，加入辅因子会导致突变酶的结构发生显著变化，导致四聚体形式解离为二聚体和单体形式。
