Entity–relationship diagram of T4SS database. Entities are represented by boxes and relationships by lines joining the boxes. The general information of the genes found in the ORF entity. Each entity ORF is related to information from biological database (InterPro, Swiss-Prot, Kegg, etc.) and tools (Psort, Phobius, etc.). Gene annotations and annotator entities are described in Annotation and User, respectively. The identified clusters are described by the entity Clusters_Names.