Crystal structure of a Y35G mutant of bovine pancreatic trypsin inhibitor.
Crystal structure of a Y35G mutant of bovine pancreatic trypsin inhibitor.
复制标题
牛胰蛋白酶抑制剂 Y35G 突变体的晶体结构。
DOI：
10.1016/0022-2836(91)90115-m
复制
发表时间：
1991
影响因子：
5.6
通讯作者：
Wlodawer,A
中科院分区：
文献类型：
--
作者：
Housset,D;Kim,KS;Fuchs,J;Woodward,C;Wlodawer,A
牛胰蛋白酶抑制剂（BPTI） Y35G突变体的结构采用分子置换法求解，并采用模拟退火和约束最小二乘法在1·8 Å分辨率下进行了细化。晶体属于空间群P4 2 2 1 2，晶胞尺寸a= b= 46·75 a∶∶c= 50·61 a∶∶最终的r因子为0.159，键距的理想偏差为0.02 Å。突变体的结构与天然蛋白不同，主链原子的总体均方根（rms）差异为1·86 Å。然而，这种变化主要集中在两个环（分别为2·04 Å和3·93 Å）和C端（分别为6·79 Å），而蛋白质的核心部分则很好地保守（rms为0·45 Å）。环路区域的变化可以清楚地归因于突变，而C端的差异可能只是由于不同的晶体包装。模型中包含了70个水分子，但其中只有7个与天然结构相同。热参数与野生型BPTI表现出良好的相关性。
The structure of a Y35G mutant of bovine pancreatic trypsin inhibitor (BPTI) was solved by molecular replacement and was refined by both simulated annealing and restrained leastsquares at 1· 8 Å resolution. The crystals belong to the space group P4 2 2 1 2, with unit cell dimensions a= b= 46· 75 A ̊, c= 50· 61 A ̊. The final R-factor is 0· 159 and the deviation from ideality for bond distances is 0· 02 Å. The structure of the mutant differs from that of the native protein, showing an overall root-mean-square (rms) difference of 1· 86 Å for mainchain atoms. However, the change is mostly localized in the two loops (respective rms values of 2· 04 Å and 3· 93 Å) and the C terminus (rms 6· 79 Å), while the core of the protein is well conserved (rms 0· 45 Å). The change in the loop regions can be clearly attributed to the mutation while the difference in the C terminus might be only due to a different crystal packing. Seventy water molecules were included in the model but only seven of them are shared with the native structure. Thermal parameters are showing a good correlation with those for the wild-type of BPTI.