1S. Wodak et al. (IUCR Computing School) Procedures for Assessing the Quality of X–Ray Structures of Macromolecules

Two approaches for assessing the quality of protein X–ray structures are presented. One, implemented in the software PROVE, is based on the calculation of atomic volumes and uses the deviation from standard volumes, computed from a reference set of very accurate protein structures, to assess the quality of an atomic model, as a whole, and in specific regions of the model. The other, implemented in the soft-ware SF–CHECK, uses several objective criteria for eva-luating the experimental structure factor data, when the latter are deposited, and for assessing the agreement of the atomic coordinates with these data, both for the model as a whole and on a per–residue basis. A combination of such tools with existing procedures like PROCHECK may rep-resent the backbone of routine structure validation proto-cols in the future.