Weber P C, Sheriff S, Ohlendorf D H, Finzel B C, Salemme F R
Proc Natl Acad Sci U S A. 1985 Dec;82(24):8473-7. doi: 10.1073/pnas.82.24.8473.
The crystal structure of Lys-7-(dinitrophenylene)-Lys-41-cross-linked ribonuclease A has been determined by molecular replacement and refined by restrained least-squares methods to an R factor of 0.18 at 2.0-A resolution. Diffraction intensity data were collected by using a conventional diffractometer and an x-ray area detector. Comparison of the thermostable cross-linked protein and the native enzyme shows them to be structurally similar, with a rms difference in backbone and side-chain atoms of 0.52 and 1.34 A, respectively. Native and modified proteins additionally show 35 common bound solvent sites and similar overall temperature factor behavior, despite localized differences resulting from cross-link introduction, altered crystal pH, or lattice interactions with neighboring molecules. These results are discussed in the context of proposals on the origins of thermostability in the cross-linked enzyme.
通过分子置换法确定了赖氨酸-7-（二硝基苯撑）-赖氨酸-41交联核糖核酸酶A的晶体结构，并采用约束最小二乘法进行精修，在2.0埃分辨率下R因子为0.18。使用传统衍射仪和X射线面积探测器收集衍射强度数据。热稳定交联蛋白与天然酶的比较表明，它们在结构上相似，主链和侧链原子的均方根偏差分别为0.52埃和1.34埃。尽管交联引入、晶体pH值改变或与相邻分子的晶格相互作用导致局部差异，但天然蛋白和修饰蛋白还显示出35个共同的结合溶剂位点以及相似的整体温度因子行为。在关于交联酶热稳定性起源的提议背景下讨论了这些结果。
