SCOP, structural classification of proteins database: Applications to evaluation of the effectiveness of sequence alignment methods and statistics ofprotein structural data

The Structural Classification of Proteins (SCOP) database provides a detail ed and comprehensive description of the relationships of all known protein structures. The classification is on hierarchical levels: the first two lev els, family and superfamily, describe near and far evolutionary relationshi ps; the third, fold, describes geometrical relationships. The distinction b etween evolutionary relationships and those that arise from the physics and chemistry of proteins is a feature that is unique to this database, so far . The database can be used as a source of data to calibrate sequence search algorithms and for the generation of population statistics on protein stru ctures. The database and its associated files are freely accessible from a number of WWW sites mirrored from URL http://scop.mrc-lmb. cam.ac.uk/scop/.