Schiffer C A, Huber R, Wüthrich K, van Gunsteren W F
Laboratory of Physical Chemistry, ETH-Zentrum, Zürich, Switzerland.
J Mol Biol. 1994 Aug 26;241(4):588-99. doi: 10.1006/jmbi.1994.1533.
The structure of the bovine pancreatic trypsin inhibitor (BPTI) has been determined to high resolution by both NMR spectroscopy in solution and X-ray diffraction in crystals. The root-mean-square difference calculated between the two structures for the polypeptide backbone is 0.9 A. Several amino acid side-chains, of which all but one are charged or polar, have different conformations. We find that by refining one structure simultaneously against both the NMR and crystallographic data sets, it can accommodate both. Different starting configurations were used, including the X-ray structure 5pti, an NMR conformer, and the X-ray structure in the full unit cell with extra solvent placed in the bulk solvent region. The X-ray structures quickly converged to accommodate the NMR data in addition to the crystallographic data. Starting from an NMR conformer, however, the convergence to accommodate the more abundant X-ray data in addition to the NMR data is much slower.
通过溶液中的核磁共振光谱法和晶体中的X射线衍射法，已将牛胰蛋白酶抑制剂（BPTI）的结构测定到高分辨率。多肽主链的两种结构之间计算出的均方根差异为0.9埃。几个氨基酸侧链，除一个外其余均带电荷或呈极性，具有不同的构象。我们发现，通过同时针对核磁共振和晶体学数据集对一种结构进行精修，它可以同时适应这两种数据。使用了不同的起始构型，包括X射线结构5pti、一种核磁共振构象异构体，以及在整体溶剂区域放置了额外溶剂的完整晶胞中的X射线结构。X射线结构迅速收敛，以除了晶体学数据之外还适应核磁共振数据。然而，从核磁共振构象异构体开始，除了核磁共振数据之外还适应更丰富的X射线数据的收敛速度要慢得多。
