本文报道的天花粉蛋白晶体中水的结构模型,包括了133个水分子,其中118个同蛋白的原子成氢键。天花粉蛋白内部有4个分立的水分子,其中2个水分子W251和W252分剔与A5螺旋变形部位的残基156Gln和157Ser的侧链成氢键,对维持活性部位的构象有贡献。晶体中水结构的比较结果表明,核糖体接近蛋白时,会诱导蛋白活性部位残基的构象发生变化,使各催化基团按催化效果最佳的构象排布,并激活一个水分子(W257)直接参与核糖体失活作用。 The structure model of water in Trichosanthin crystal reported in this paper includes 133 water molecules, of which 118 hydrogen bonds with the protein. Trichosanthin internal four discrete water molecules, of which two water molecules W251 and W252 tick tick A5G helical deformation residues 156Gln and 157Ser side chain hydrogen bonding, to maintain the conformation of the active site contribute. The results of water structure comparison show that when the ribosome approaches the protein, the conformation of residues in the active site of the protein is induced to change, so that the catalytic groups are arranged in the best catalytic conformation and activate a water molecule (W257) Directly involved in ribosome inactivation.