UniProt functional annotation for P54308



	UniProt functional annotation for P54308

UniProt code: P54308.

Organism: Bacillus phage SPP1 (Bacteriophage SPP1).

Taxonomy: Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes; Caudovirales; Siphoviridae.

Function: The terminase large subunit acts as an ATP driven molecular motor necessary for viral DNA translocation into empty capsids and as an endonuclease that cuts the viral genome to initiate and to end a packaging reaction (PubMed:10930407). The terminase lies at a unique vertex of the procapsid and is composed of two subunits, a small terminase subunit involved in viral DNA recognition (packaging sequence), and a large terminase subunit possessing endonucleolytic and ATPase activities (PubMed:23419885). Both terminase subunits heterooligomerize and are docked on the portal protein to form the packaging machine (PubMed:23419885). The terminase large subunit exhibits endonuclease activity and cleaves the viral genome concatemer once the capsid is full (headful packaging) (Probable) (PubMed:10930407). Once the capsid is packaged with the DNA, the terminase complex is substituted by the adapter (gp15) and the stopper protein (gp16) that form the connector (Probable). {ECO:0000255|HAMAP- Rule:MF_04145, ECO:0000269|PubMed:10930407, ECO:0000269|PubMed:23419885, ECO:0000305|PubMed:23419885}.

Cofactor: Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000255|HAMAP-Rule:MF_04145, ECO:0000269|PubMed:19444313}; Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255|HAMAP-Rule:MF_04145, ECO:0000269|PubMed:10930407}; Note=Binds 2 divalent metal cations per subunit. Mn(2+) is preferred over Mg(2+) (By similarity). Optimum concentration of Mg(2+) is 10 mm (PubMed:10930407). As the Mn(2+) dose increases, gp2 converts supercoiled circular plasmid DNA to nicked open circular DNA, subsequently to linear DNA and finally to completely degraded DNA (PubMed:19444313). {ECO:0000255|HAMAP-Rule:MF_04145, ECO:0000269|PubMed:10930407, ECO:0000269|PubMed:19444313};

Biophysicochemical properties: pH dependence: Optimum pH is 7.8. {ECO:0000269|PubMed:10930407};

Subunit: Monomer. Interacts with the terminase small subunit; the active complex is probably composed of two decameric ring-shaped terminase small subunit and two monomeric terminase large subunit (PubMed:12697751). Interacts with the portal protein (PubMed:23118480, PubMed:12697751). {ECO:0000255|HAMAP-Rule:MF_04145, ECO:0000269|PubMed:12697751, ECO:0000269|PubMed:23118480}.

Domain: The N-terminus contains an ATPase domain and the C-terminus contains an endonuclease domain. {ECO:0000255|HAMAP-Rule:MF_04145, ECO:0000269|PubMed:16377618}.

Annotations taken from UniProtKB at the EBI.


Organism:		Bacillus phage SPP1 (Bacteriophage SPP1).
Taxonomy:		Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes; Caudovirales; Siphoviridae.



Function:		The terminase large subunit acts as an ATP driven molecular motor necessary for viral DNA translocation into empty capsids and as an endonuclease that cuts the viral genome to initiate and to end a packaging reaction (PubMed:10930407). The terminase lies at a unique vertex of the procapsid and is composed of two subunits, a small terminase subunit involved in viral DNA recognition (packaging sequence), and a large terminase subunit possessing endonucleolytic and ATPase activities (PubMed:23419885). Both terminase subunits heterooligomerize and are docked on the portal protein to form the packaging machine (PubMed:23419885). The terminase large subunit exhibits endonuclease activity and cleaves the viral genome concatemer once the capsid is full (headful packaging) (Probable) (PubMed:10930407). Once the capsid is packaged with the DNA, the terminase complex is substituted by the adapter (gp15) and the stopper protein (gp16) that form the connector (Probable). {ECO:0000255\|HAMAP- Rule:MF_04145, ECO:0000269\|PubMed:10930407, ECO:0000269\|PubMed:23419885, ECO:0000305\|PubMed:23419885}.


Cofactor:		Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000255\|HAMAP-Rule:MF_04145, ECO:0000269\|PubMed:19444313}; Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000255\|HAMAP-Rule:MF_04145, ECO:0000269\|PubMed:10930407}; Note=Binds 2 divalent metal cations per subunit. Mn(2+) is preferred over Mg(2+) (By similarity). Optimum concentration of Mg(2+) is 10 mm (PubMed:10930407). As the Mn(2+) dose increases, gp2 converts supercoiled circular plasmid DNA to nicked open circular DNA, subsequently to linear DNA and finally to completely degraded DNA (PubMed:19444313). {ECO:0000255\|HAMAP-Rule:MF_04145, ECO:0000269\|PubMed:10930407, ECO:0000269\|PubMed:19444313};
Biophysicochemical properties:		pH dependence: Optimum pH is 7.8. {ECO:0000269\|PubMed:10930407};
Subunit:		Monomer. Interacts with the terminase small subunit; the active complex is probably composed of two decameric ring-shaped terminase small subunit and two monomeric terminase large subunit (PubMed:12697751). Interacts with the portal protein (PubMed:23118480, PubMed:12697751). {ECO:0000255\|HAMAP-Rule:MF_04145, ECO:0000269\|PubMed:12697751, ECO:0000269\|PubMed:23118480}.
Domain:		The N-terminus contains an ATPase domain and the C-terminus contains an endonuclease domain. {ECO:0000255\|HAMAP-Rule:MF_04145, ECO:0000269\|PubMed:16377618}.