Fourmy D, Dardel F, Blanquet S
Laboratoire de Biochimie, URA 240 CNRS Ecole Polytechnique, Palaiseau, France.
J Mol Biol. 1993 Jun 20;231(4):1078-89. doi: 10.1006/jmbi.1993.1353.
Methionyl-tRNA synthetase from Escherichia coli contains one tightly bound zinc atom per subunit. The region encompassing residues 138 to 163 of this enzyme is responsible for the metal binding. A 28-mer peptide corresponding to these residues was expressed in vivo and shown to contain approximately 1 mol of tightly bound Zn/mol of peptide. In this study, the three-dimensional solution structure of this peptide was solved by means of two-dimensional proton NMR spectroscopy. A total of 133 nuclear Overhauser effect distance constraints and 22 dihedral angle restraints were used for the calculations, using a hybrid distance-geometry-simulated annealing strategy. Excluding the first four residues, the resulting structure is well-defined (r.m.s.d. 0.71 A for backbone atoms) and composed of a series of four tight turns. The second and the fourth turns are composed of CXXC sequences which are structurally homologous to the NH-S turns found in the metal binding sites of gag retroviral proteins and rubredoxin. The solution structure of the zinc binding peptide shows significant discrepancies with the crystal structure of methionyl-tRNA synthetase.
来自大肠杆菌的甲硫氨酰 - tRNA合成酶每个亚基含有一个紧密结合的锌原子。该酶中包含138至163位残基的区域负责金属结合。与这些残基对应的一个28肽在体内表达，并显示每摩尔肽含有约1摩尔紧密结合的锌。在本研究中，通过二维质子核磁共振光谱法解析了该肽的三维溶液结构。计算使用了总共133个核Overhauser效应距离约束和22个二面角约束，采用了混合距离几何 - 模拟退火策略。排除前四个残基后，所得结构定义明确（主链原子的均方根偏差为0.71 Å），由一系列四个紧密转角组成。第二个和第四个转角由CXXC序列组成，这些序列在结构上与在逆转录病毒gag蛋白和红素氧还蛋白的金属结合位点中发现的NH - S转角同源。锌结合肽的溶液结构与甲硫氨酰 - tRNA合成酶的晶体结构存在显著差异。
