UniProt: The Universal Protein Resource
The Universal Protein Resource (UniProt) is a comprehensive resource for protein sequence and functional annotation data. UniProt comprises four major components, each optimised for different uses. The UniProt Knowledgebase (UniProtKB) is an expertly curated database, and a central access point for integrated protein information with cross-references to multiple sources. The UniProt Archive (UniParc) is a comprehensive sequence repository, reflecting the history of all protein sequences. UniProt Reference Clusters (UniRef) merge closely related sequences based on sequence identity to speed up searches while the UniProt Metagenomic and Environmental Sequences database (UniMES) was created to respond to the expanding area of metagenomic data.