Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Box 8103, St. Louis, MO 63110, USA.
Arch Biochem Biophys. 2012 Mar 15;519(2):175-85. doi: 10.1016/j.abb.2011.10.005. Epub 2011 Oct 15.
D-3-Phosphoglycerate dehydrogenases (PGDH) exist with at least three different structural motifs and the enzymes from different species display distinctly different mechanisms. In many species, particularly bacteria, the catalytic activity is regulated allosterically through binding of l-serine to a distinct structural domain, termed the ACT domain. Some species, such as Mycobacterium tuberculosis, contain an additional domain, called the "allosteric substrate binding" or ASB domain, that functions as a co-domain in the regulation of catalytic activity. That is, both substrate and effector function synergistically in the regulation of activity to give the enzyme some interesting properties that may have physiological relevance for the persistent state of tuberculosis. Both enzymes function through a V-type regulatory mechanism and, in the Escherichia coli enzyme, it has been demonstrated that this results from a dead-end complex that decreases the concentration of active species rather than a decrease in the velocity of the active species. This review compares and contrasts what we know about these enzymes and provides additional insight into their mechanism of allosteric regulation.
D-3-磷酸甘油酸脱氢酶 (PGDH) 至少存在三种不同的结构基序，不同物种的酶表现出明显不同的机制。在许多物种中，特别是细菌，通过 l-丝氨酸结合到一个称为 ACT 结构域的独特结构域，对催化活性进行别构调节。一些物种，如结核分枝杆菌，含有一个称为“别构底物结合”或 ASB 结构域的附加结构域，在调节催化活性中作为协同结构域发挥作用。也就是说，底物和效应物协同作用调节活性，使酶具有一些有趣的特性，这些特性可能与结核病的持续状态具有生理相关性。两种酶都通过 V 型调节机制发挥作用，在大肠杆菌酶中，已经证明这是由于终产物复合物的形成降低了活性物质的浓度，而不是降低了活性物质的速度。本综述比较和对比了我们对这些酶的了解，并提供了对其别构调节机制的深入了解。
