Kravchenko O V, Kislitsin Yu A, Popov A N, Nikonov S V, Kuranova I P
Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
Acta Crystallogr D Biol Crystallogr. 2008 Mar;64(Pt 3):248-56. doi: 10.1107/S0907444907065766. Epub 2008 Feb 20.
The crystal structures of Erwinia carotovora L-asparaginase complexed with L-aspartate and L-glutamate were determined at 1.9 and 2.2 A, respectively, using the molecular-replacement method and were refined to R factors of about 21% in both cases. The positions of the ligands in the active site were located. A comparison of the new structures with the known structures of Escherichia coli L-asparaginase and Er. chrysanthemi L-asparaginase was performed. It was found that the arrangement of the ligands practically coincides in all three enzymes. The peculiarities of the quaternary structure of the enzyme, the possible role of water molecules in the enzyme action and the conformational changes during the catalyzed reaction are discussed.
利用分子置换法分别测定了胡萝卜软腐欧文氏菌L-天冬酰胺酶与L-天冬氨酸和L-谷氨酸复合物的晶体结构，分辨率分别为1.9 Å和2.2 Å，两种情况下均将结构精修至约21%的R因子。确定了活性位点中配体的位置。将这些新结构与大肠杆菌L-天冬酰胺酶和菊欧文氏菌L-天冬酰胺酶的已知结构进行了比较。结果发现，所有这三种酶中配体的排列几乎一致。讨论了该酶四级结构的特点、水分子在酶作用中的可能作用以及催化反应过程中的构象变化。
