Kudou Daizou, Misaki Shintaro, Yamashita Masao, Tamura Takashi, Takakura Tomoaki, Yoshioka Takayuki, Yagi Shigeo, Hoffman Robert M, Takimoto Akio, Esaki Nobuyoshi, Inagaki Kenji
Department of Biofunctional Chemistry, Graduate School of Natural Science and Technology, Okayama University, Okayama-Shi, Okayama, Japan.
J Biochem. 2007 Apr;141(4):535-44. doi: 10.1093/jb/mvm055. Epub 2007 Feb 8.
l-Methionine gamma-lyase (EC 4.4.1.11, MGL_Pp) from Pseudomonas putida is a multifunctional enzyme, which belongs to the gamma-family of pyridoxal-5'-phosphate (PLP) dependent enzymes. In this report, we demonstrate that the three-dimensional structure of MGL_Pp has been completely solved by the molecular replacement method to an R-factor of 20.4% at 1.8 A resolution. Detailed information of the overall structure of MGL_Pp supplies a clear picture of the substrate- and PLP-binding pockets. Tyr59 and Arg61 of neighbouring subunits, which are strongly conserved in other gamma-family enzymes, contact the phosphate group of PLP. These residues are important as the main anchor within the active site. Lys240, Asp241 and Arg61 of one partner monomer and Tyr114 and Cys116 of the other partner monomer form a hydrogen-bond network in the MGL active site which is specific for MGLs. It is also suggested that electrostatic interactions at the subunit interface are involved in the stabilization of the structural conformation. The detailed structure will facilitate the development of MGL_Pp as an anticancer drug.
来自恶臭假单胞菌的L-甲硫氨酸γ-裂合酶（EC 4.4.1.11，MGL_Pp）是一种多功能酶，属于依赖于磷酸吡哆醛（PLP）的γ-家族酶。在本报告中，我们证明通过分子置换法已完全解析出MGL_Pp的三维结构，在1.8埃分辨率下R因子为20.4%。MGL_Pp整体结构的详细信息清晰呈现了底物和PLP结合口袋的情况。相邻亚基的Tyr59和Arg61在其他γ-家族酶中高度保守，它们与PLP的磷酸基团接触。这些残基作为活性位点内的主要锚定物很重要。一个伙伴单体的Lys240、Asp241和Arg61以及另一个伙伴单体的Tyr114和Cys116在MGL活性位点形成了一个对MGL特异的氢键网络。还表明亚基界面处的静电相互作用参与了结构构象的稳定。详细结构将有助于开发MGL_Pp作为一种抗癌药物。
