Smith D L, Almo S C, Toney M D, Ringe D
Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.
Biochemistry. 1989 Oct 3;28(20):8161-7. doi: 10.1021/bi00446a030.
The three-dimensional structure of a mutant of the aspartate aminotransferase from Escherichia coli, in which the active-site lysine has been substituted by alanine (K258A), has been determined at 2.8-A resolution by X-ray diffraction. The mutant enzyme contains pyridoxamine phosphate as cofactor. The structure is compared to that of the mitochondrial aspartate aminotransferase. The most striking differences, aside from the absence of the lysine side chain, occur in the positions of the pyridoxamine group and of tryptophan 140.
已通过X射线衍射在2.8埃分辨率下测定了来自大肠杆菌的天冬氨酸转氨酶突变体的三维结构，该突变体中活性位点的赖氨酸已被丙氨酸取代（K258A）。该突变体酶含有磷酸吡哆胺作为辅因子。将该结构与线粒体天冬氨酸转氨酶的结构进行了比较。除了赖氨酸侧链缺失外，最显著的差异出现在磷酸吡哆胺基团和色氨酸140的位置。
