Proteins are generally composed of one or more functional regions, commonly termed domains. Domain annotation resources such as CATH provide curated domain assignments and a grouping of domains into families sharing evidence of homology (superfamilies). Although not a one to one relationship, a given domain superfamily will have a limited number of functions that its members fulfill in the whole-protein context. The combination of domains from different superfamilies gives rise to novel protein functions. Therefore, identifying the domains in a protein can give useful insights into protein function.

Finer grained groupings of superfamilies based on function (FunFams), and structure (SCs) are also provided. Gene3D is also unique in that it provides example of nested domains, where a given domain may have been inserted into another during evolution.

Search for proteins using gene names, protein IDs and keywords

Search for proteins in a species by superfamily code or name

Search for proteins interactions using gene names, protein IDs and keywords

Retrieve functional, structural and taxonomic superfamily information

Compare superfamily compositions between two genomes

Display frequency of superfamily accross Ensembl Genomes