3-DIMENSIONAL STRUCTURES OF ASPARTATE-AMINOTRANSFERASE FROM ESCHERICHIA-COLI AND ITS MUTANT ENZYME AT 2.5-A RESOLUTION
3-DIMENSIONAL STRUCTURES OF ASPARTATE-AMINOTRANSFERASE FROM ESCHERICHIA-COLI AND ITS MUTANT ENZYME AT 2.5-A RESOLUTION
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DOI：
10.1093/oxfordjournals.jbchem.a123178
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发表时间：
1990-08-01
影响因子：
2.7
通讯作者：
KATSUBE, Y
中科院分区：
文献类型：
--
作者：
KAMITORI, S;OKAMOTO, A;KATSUBE, Y
在2.5埃下测定大肠杆菌天冬氨酸氨基转移酶与抑制剂2-甲基天冬氨酸复合物的结构，以及突变酶的结构，其中精氨酸取代赖氨酸残基，从而与辅酶吡哆醛5“-磷酸形成希夫碱。分辨率，通过分子置换法使用已知结构的猪胞质天冬氨酸氨基转移酶。该酶催化L-天冬氨酸和α-天冬氨酸之间的可逆转氨作用。酮戊二酸，并形成两个相同亚基的二聚体结构。每个亚基包含两个结构域，一个小的和一个大的。尽管E.大肠杆菌的酶与高等动物的酶相似，但酶的作用与高等动物的酶有一定的差异。大肠杆菌和高等动物的X-射线结构和分子力学计算结果可以解释这些结构。
The structure of Escherichia coli aspartate aminotransferase complex with the inhibitor 2-methylaspartate, and that of the mutant enzyme in which an arginine was substituted for a lysine residue thereby forming a Schiff base with the coenzyme pyridoxal 5''-phosphate, were determined at 2.5 .ANG. resolution, by the molecular replacement method using the known structure of pig cytosolic aspartate aminotransferase. The enzyme catalyzes the reversible transamination between L-aspartate and .alpha.-ketoglutarate, and forms a dimeric structure of two identical subunits. Each subunit comprises two domains, a small and a large one. Although, in general, the overall and secondary structures of E. coli enzyme are similar to those of higher animals, some differences of enzymatic action between the enzyme from E. coli and those from higher animals could be explained on the basis of the X-ray structures and molecular mechanics calculation based on them.