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Annotation rule MF_04145
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General rule information [?]

Accession MF_04145
Dates 17-JAN-2020 (Created)
7-FEB-2020 (Last updated, Version 4)
Viruses; Caudovirales
Template P54308 (TERL_BPSPP)

Propagated annotation [?]

Identifier, protein and gene names [?]

Protein name
RecName: Full=Terminase, large subunit;
AltName: Full=DNA-packaging protein;
RecName: Full=Endonuclease;
EC 3.1.-.-;
RecName: Full=ATPase;
EC 3.6.4.-;

Comments [?]

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. 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. Both terminase subunits heterooligomerize and are docked on the portal protein to form the packaging machine. The terminase large subunit exhibits endonuclease activity and cleaves the viral genome concatemer once the capsid is full (headful packaging). Once the capsid is packaged with the DNA, the terminase complex is substituted by the adapter and the stopper protein that form the connector.
case <FTGroup:1>
Cofactor Mn(2+)
Note: Binds 2 divalent metal cations per subunit. Mn(2+) is preferred over Mg(2+).
end case
Subunit Monomer. Interacts with the terminase small subunit; the active complex is probably heterooligomeric. Interacts with the portal protein.
Domain The N-terminus contains an ATPase domain and the C-terminus contains an endonuclease domain.

Keywords [?]

case <FTGroup:1>
end case

Gene Ontology [?]

GO:0098009; Cellular component: viral terminase, large subunit.
GO:0004519; Molecular function: endonuclease activity.
GO:0046872; Molecular function: metal ion binding.
GO:0004518; Molecular function: nuclease activity.
GO:0006323; Biological process: DNA packaging.
GO:0019073; Biological process: viral DNA genome packaging.

Cross-references [?]

Pfam PF04466; Terminase_3; 1;
PF17288; Terminase_3C; 1;
TIGRFAMs TIGR01547; phage_term_2; 1;

Features [?]

From: TERL_BPSPP (P54308)
Key     From     To       Description   Tag   Condition   FTGroup
REGION     1     198       ATPase activity        
REGION     232     422       Nuclease activity and binding to the portal protein        
MOTIF     33     40       Walker A motif     G-[GS]-[AR]-[AG]-S-[AGK]-[AGK]-S  
MOTIF     130     135       Walker B motif     x-[CAGLM]-W-[IFY]-E-E  
ACT_SITE     135     135       For ATPase activity     E  
METAL     266     266       Manganese 1; catalytic; for nuclease activity     D   1
METAL     266     266       Manganese 2; catalytic; for nuclease activity     D   1
METAL     321     321       Manganese 1; catalytic; for nuclease activity     D   1
METAL     400     400       Manganese 2; catalytic; for nuclease activity     H   1
METAL     403     403       Manganese 2; catalytic; for nuclease activity     D   1

Additional information [?]

Size range 370-540 amino acids
Related rules None
Fusion None