Inagaki Eiji, Ohshima Noriyasu, Takahashi Hitomi, Kuroishi Chizu, Yokoyama Shigeyuki, Tahirov Tahir H
RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
J Mol Biol. 2006 Sep 22;362(3):490-501. doi: 10.1016/j.jmb.2006.07.048. Epub 2006 Jul 29.
Delta(1)-pyrroline-5-carboxylate dehydrogenase (P5CDh) plays an important role in the metabolic pathway from proline to glutamate. It irreversibly catalyzes the oxidation of glutamate-gamma-semialdehyde, the product of the non-enzymatic hydrolysis of Delta(1)-pyrroline-5-carboxylate, into glutamate with the reduction of NAD(+) into NADH. We have confirmed the P5CDh activity of the Thermus thermophilus protein TT0033 (TtP5CDh), and determined the crystal structure of the enzyme in the ligand-free form at 1.4 A resolution. To investigate the structural basis of TtP5CDh function, the TtP5CDh structures with NAD(+), with NADH, and with its product glutamate were determined at 1.8 A, 1.9 A, and 1.4 A resolution, respectively. The solved structures suggest an overall view of the P5CDh catalytic mechanism and provide insights into the P5CDh deficiencies in the case of the human type II hyperprolinemia.
δ¹-吡咯啉-5-羧酸脱氢酶（P5CDh）在从脯氨酸到谷氨酸的代谢途径中起重要作用。它不可逆地催化δ¹-吡咯啉-5-羧酸非酶水解产物谷氨酸-γ-半醛氧化为谷氨酸，同时将NAD⁺还原为NADH。我们已证实嗜热栖热菌蛋白TT0033（TtP5CDh）的P5CDh活性，并以1.4 Å分辨率测定了该酶无配体形式的晶体结构。为研究TtP5CDh功能的结构基础，分别以1.8 Å、1.9 Å和1.4 Å分辨率测定了TtP5CDh与NAD⁺、与NADH及其产物谷氨酸结合的结构。解析出的结构揭示了P5CDh催化机制的整体情况，并为人类II型高脯氨酸血症中P5CDh缺陷提供了见解。
