Protein Domain : Terminase small subunit IPR005335

Type	Family
Description	Packaging of double-stranded viral DNA concatemers requires interaction of the prohead with virus DNA. This process is mediated by a phage-encoded DNA recognition and terminase protein. The terminase enzymes described so far, which are hetero-oligomers composed of a small and a large subunit, do not have a significant level of sequence homology. The small terminase subunit is thought to form a nucleoprotein structure that helps to position the terminase large subunit at the packaging initiation site [ ]. The small terminase protein is essential for the initial recognition of viral DNA and regulates the motor's ATPase and nuclease activities during DNA translocation [] and for switching between viral DNA replication and packaging. DNA packaging in tailed bacteriophages and in evolutionarily related herpesviruses is controlled by a viral-encoded terminase. The terminase complex characterised in Bacillus subtilis bacteriophages SF6 and SPP1 consists of two proteins: G1P and G2P [, ].
Short Name	Terminase_ssu