嗜热栖热菌异丙基苹果酸脱氢酶中底物结合的建模
Modeling substrate binding in Thermus thermophilus isopropylmalate dehydrogenase.
作者信息
Zhang T, Koshland D E
机构信息
Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
出版信息
Protein Sci. 1995 Jan;4(1):84-92. doi: 10.1002/pro.5560040111.
The Thermus thermophilus 3-isopropylmalate dehydrogenase (IPMDH) and Escherichia coli isocitrate dehydrogenase (ICDH) are two functionally and evolutionarily related enzymes with distinct substrate specificities. To understand the determinants of substrate specificities of the two proteins, the substrate and coenzyme in IPMDH were docked into their respective binding sites based on the published structure for apo IPMDH and its sequence and structural homology to ICDH. This modeling study suggests that (1) the substrate and coenzyme (NAD) binding modes of IPMDH are significantly different from those of ICDH, (2) the interactions between the substrates and coenzymes help explain the differences in substrate specificities of IPMDH and ICDH, and (3) binding of the substrate and coenzyme should induce a conformational change in the structure of IPMDH.
嗜热栖热菌3-异丙基苹果酸脱氢酶（IPMDH）和大肠杆菌异柠檬酸脱氢酶（ICDH）是两种在功能和进化上相关但具有不同底物特异性的酶。为了理解这两种蛋白质底物特异性的决定因素，基于已发表的脱辅基IPMDH结构及其与ICDH的序列和结构同源性，将IPMDH中的底物和辅酶对接至它们各自的结合位点。该建模研究表明：（1）IPMDH的底物和辅酶（NAD）结合模式与ICDH的显著不同；（2）底物与辅酶之间的相互作用有助于解释IPMDH和ICDH底物特异性的差异；（3）底物和辅酶的结合应诱导IPMDH结构发生构象变化。
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