ESCHERICHIA-COLI ASPARTATE-TRANSCARBAMYLASE - THE RELATION BETWEEN STRUCTURE AND FUNCTION
ESCHERICHIA-COLI ASPARTATE-TRANSCARBAMYLASE - THE RELATION BETWEEN STRUCTURE AND FUNCTION
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DOI：
10.1126/science.3041592
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发表时间：
1988-08-05
期刊：
影响因子：
56.9
通讯作者：
LIPSCOMB, WN
中科院分区：
文献类型：
--
作者：
KANTROWITZ, ER;LIPSCOMB, WN
大肠杆菌的变构酶天冬氨酸转甲氨基酰基酶的x射线结构已经被解决并改进为两种变构形式。T型在异向抑制剂cytidine triphosphate （CTP）存在的情况下确定，而R型在双底物类似物n -phosphonacetyl- l-天冬氨酸存在的情况下确定。这两种x射线结构为理解变构酶如何能够控制代谢途径的速率提供了起点。基于这些x射线结构，通过使用位点定向诱变来探测被认为对酶功能至关重要的残基，对催化和同向性协同作用的机制有了深入的了解。
The x-ray structures of the allosteric enzyme aspartate transcarbamylase fromEscherichia colihave been solved and refined for both allosteric forms. The T form was determined in the presence of the heterotropic inhibitor cytidine triphosphate, CTP, while the R form was determined in the presence of the bisubstrate analogN-phosphonacetyl-L-aspartate. These two x-ray structures provide the starting point for an understanding of how allosteric enzymes are able to control the rates of metabolic pathways. Insights into the mechanisms of both catalysis and homotropic cooperativity have been obtained by using site-directed mutagenesis to probe residues thought to be critical to the function of the enzyme based on these x-ray structures.