期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：6
页码：2133-2137
DOI：10.1073/pnas.79.6.2133
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：A potential energy-constrained real-space refinement method designed for use with x-ray diffraction data of low to moderate resolution has been developed. The number of adjustable parameters is severely restricted to ensure a reasonable ratio of data to parameters. Only dihedral angles are allowed to vary; bond lengths and bond angles are fixed at physically reasonable values. The structure of bovine pancreatic trypsin inhibitor was refined by using this method with data to only 2.5-A resolution. Both the R-factor and the electron-density map improved throughout the refinement, and the final structure was a satisfactory approximation to the 1.5-A structure.
关键词：UNICEPP potential energy function ; bovine pancreatic trypsin inhibitor ; x-ray diffraction data
