KNOWLEDGE-BASED VALIDATION OF PROTEIN-STRUCTURE COORDINATES DERIVED BY X-RAY CRYSTALLOGRAPHY AND NMR-SPECTROSCOPY

Over the past few years, several protein structures solved by X-ray crystallography have been found to contain serious errors. This has prompted the development of methods for validating protein structures, in both the X-ray and NMR fields. A number of computational tools have recently been developed for assessing structures independently of the experimental data, thereby providing an additional, complementary check on their correctness. In effect, the tests assess the normality of a protein and are both local, checking the correctness of the local geometry, and global, verifying the overall fold. In structure determination by NMR the problems or validation are compounded by multiple solutions for the experimental data and lack of agreement over means of assessing the fit of the models to the data.