What is the Complex Portal?


The Complex Portal is a manually curated, encyclopedic resource of macromolecular complexes from a number of key model organisms. Complexes contain proteins as well as small molecules and nucleic acids as long as they are integral parts of the complex.

Evidence for complexes is derived from one or more of the following methods:

1) Physical molecular interaction and functional evidence extracted from the literature

2) Inferred by curators from information on orthologues in closely-related species or paralogues in the same species where the original complex has experimental evidence

3) Inferred by curators from background biological knowledge based on other evidence (for example, pharmacological studies).

Controlled vocabulary terms from the Evidence Code Ontology are used to identify and tag evidence.

The data in the Complex Portal can be searched and downloaded interactively or by programmatic access.

The details pages for any given complex are structured by topics: Function, Properties, Expression, Cellular Location, Diseases/Pathology, Further Reading. They contain an interactive viewer with details of stoichiometry and binding regions and provide further graphical information for Reactions and Pathways in Reactome, structures in the PDBe and expression data from the Expression Atlas.

It also provides cross-references to a given complex from many other databases, such as ChEMBL, Electron Microscopy Data Base and MatrixDB. The Portal also contains annotations to all three classes of The Gene Ontology, EC numbers, diseases and literature evidence in EuropePMC.

Content is added by expert curators and direct user requests are prioritised. It shares a database with the IntAct molecular interaction database.

Why do we need the Complex Portal?

The Complex Portal provides annotations for the whole complex (i.e. the functional biological entity), along with desciptions of their function and other properties. It differs from UniProt because the latter only provides annotations for the protein subunits.