Hartmann H, Steigemann W, Reuscher H, Parak F
Eur Biophys J. 1987;14(6):337-48. doi: 10.1007/BF00262319.
The refinement of X-ray structural data gives the mean square displacements, (chi 2), at each position in the protein molecule. In order to get information on the significance of such values different refinement methods have been compared. The metmyoglobin structure was determined at 300 K and (chi 2)-values were obtained with the restrained refinement procedure in reciprocal space of Konnert and Hendrickson. A comparison with the results of Frauenfelder et al. was used for an error estimation. The inclusion of surface bound water increases the accuracy of the results but does not change the general picture. For erythrocruorin (CTT3) a refinement was performed in reciprocal space and compared with a refinement in real space performed earlier. The (chi 2)-values obtained from both procedures are similar although the reciprocal space refinement gives results which are physically more reasonable. A comparison of the disorder in myoglobin and erythrocruorin showed that the structural similarity results in a similarity in the disorder. Contacts of molecules in the crystal do not dominate the disorder although they locally influence (chi 2)-values. CTT3 shows large disorder in the heme region in contrast to myoglobin. The differences in the rigidity of the F-helix can be correlated with the oxygen affinities supporting models for O2 binding developed by Frauenfelder et al.
X射线结构数据的精修给出了蛋白质分子中每个位置的均方根位移（χ2）。为了获取关于这些值的显著性信息，对不同的精修方法进行了比较。在300K下测定了高铁肌红蛋白的结构，并使用Konnert和Hendrickson在倒易空间中的约束精修程序获得了χ2值。与Frauenfelder等人的结果进行比较以进行误差估计。包含表面结合水提高了结果的准确性，但没有改变总体情况。对于蚯蚓血红蛋白（CTT3），在倒易空间中进行了精修，并与之前在实空间中进行的精修进行了比较。尽管倒易空间精修给出的结果在物理上更合理，但从这两种程序获得的χ2值相似。对肌红蛋白和蚯蚓血红蛋白无序情况的比较表明，结构相似性导致无序情况相似。晶体中分子间的接触虽然局部影响χ2值，但并不主导无序情况。与肌红蛋白相比，CTT3在血红素区域表现出较大的无序。F螺旋刚性的差异与氧亲和力相关，支持了Frauenfelder等人提出的O2结合模型。
