Helmstaedt K, Krappmann S, Braus G H
Abteilung Molekulare Mikrobiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität, Grisebachstr. 8, D-37077 Göttingen, Germany.
Microbiol Mol Biol Rev. 2001 Sep;65(3):404-21, table of contents. doi: 10.1128/MMBR.65.3.404-421.2001.
Allosteric regulation of key metabolic enzymes is a fascinating field to study the structure-function relationship of induced conformational changes of proteins. In this review we compare the principles of allosteric transitions of the complex classical model aspartate transcarbamoylase (ATCase) from Escherichia coli, consisting of 12 polypeptides, and the less complicated chorismate mutase derived from baker's yeast, which functions as a homodimer. Chorismate mutase presumably represents the minimal oligomerization state of a cooperative enzyme which still can be either activated or inhibited by different heterotropic effectors. Detailed knowledge of the number of possible quaternary states and a description of molecular triggers for conformational changes of model enzymes such as ATCase and chorismate mutase shed more and more light on allostery as an important regulatory mechanism of any living cell. The comparison of wild-type and engineered mutant enzymes reveals that current textbook models for regulation do not cover the entire picture needed to describe the function of these enzymes in detail.
关键代谢酶的变构调节是一个研究蛋白质诱导构象变化的结构-功能关系的迷人领域。在这篇综述中，我们比较了来自大肠杆菌的由12个多肽组成的复杂经典模型天冬氨酸转氨甲酰酶（ATCase）和来自面包酵母的较简单的、作为同型二聚体起作用的分支酸变位酶的变构转变原理。分支酸变位酶可能代表了一种协同酶的最小寡聚化状态，这种酶仍然可以被不同的异源效应物激活或抑制。对诸如ATCase和分支酸变位酶等模型酶的可能四级状态数量的详细了解以及对构象变化的分子触发因素的描述，越来越多地揭示了变构作为任何活细胞的重要调节机制。野生型和工程突变酶的比较表明，当前用于调节的教科书模型并未涵盖详细描述这些酶功能所需的全貌。
