Lee Jun Hyuck, Im Young Jun, Bae Jungdon, Kim Dooil, Kim Mun-Kyoung, Kang Gil Bu, Lee Dae-Sil, Eom Soo Hyun
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea.
Biochem Biophys Res Commun. 2006 Dec 1;350(4):1044-9. doi: 10.1016/j.bbrc.2006.09.151. Epub 2006 Oct 6.
Phosphoglycerate kinase (PGK) is a key glycolytic enzyme that catalyzes the reversible transfer of a phosphate from 1,3-bisphosphoglycerate to ADP to form 3-phosphoglycerate and ATP in the presence of magnesium. During catalysis, a conformational change occurs that brings the N- and C-domains of PGK closer together. Here we present the 1.8A crystal structure of unliganded PGK from Thermus caldophilus (Tca). Comparison of the structure of TcaPGK (open conformation) with that of Thermotoga maritima (Tma) PGK (closed conformation) revealed that the conformational change reflects a change in the interaction between the domains. We identified Arg148 as a key residue involved in open-to-closed transition. The open conformation of TcaPGK is stabilized by an interdomain salt bridge between Arg148 and Glu375. The binding of 3-PG (or maybe 1,3-BPG) disrupts this salt bridge and, in ternary complex, the formation of new salt bridge between Arg60 and Asp197 stabilizes the closed conformation.
磷酸甘油酸激酶（PGK）是一种关键的糖酵解酶，在镁存在的情况下，它催化1,3-二磷酸甘油酸上的磷酸基团可逆地转移至ADP，形成3-磷酸甘油酸和ATP。在催化过程中，会发生构象变化，使PGK的N结构域和C结构域靠得更近。在此，我们展示了嗜热栖热菌（Tca）无配体PGK的1.8埃晶体结构。将TcaPGK（开放构象）的结构与海栖热袍菌（Tma）PGK（闭合构象）的结构进行比较后发现，构象变化反映了结构域之间相互作用的改变。我们确定精氨酸148是参与从开放构象到闭合构象转变的关键残基。TcaPGK的开放构象通过精氨酸148和谷氨酸375之间的结构域间盐桥得以稳定。3-磷酸甘油酸（或可能是1,3-二磷酸甘油酸）的结合会破坏这种盐桥，在三元复合物中，精氨酸60和天冬氨酸197之间形成新的盐桥，从而稳定闭合构象。
