The SUPERFAMILY annotation is based on a collection of hidden Markov models (HMM), which represent structural protein domains at the SCOP  superfamily level.
 A superfamily groups together domains which have an evolutionary relationship.  The annotation is produced by scanning protein sequences from completely sequenced genomes against the hidden Markov models.
For each protein you can:
* Submit sequences for SCOP classification
* View domain organisation, sequence alignments and protein sequence details
For each genome you can:
* Examine superfamily assignments, phylogenetic trees, domain organisation lists and networks
* Check for over- and under-represented superfamilies within a genome
For each superfamily you can:
* Inspect SCOP classification, functional annotation, Gene Ontology annotation, InterPro abstract and genome assignments 
* Explore taxonomic distribution of a superfamily across the tree of life
All annotation, models and the database dump are freely available for download to everyone.