AC MF_04146; DC Protein; auto TR HAMAP; MF_04146; -; 1; level=0 XX Names: TERL_T4 XX ID TERL DE RecName: Full=Terminase, large subunit; DE AltName: Full=DNA-packaging protein; DE Includes: DE RecName: Full=ATPase; DE EC=3.6.4.-; DE Includes: DE RecName: Full=Endonuclease; DE EC=3.1.21.-; XX case CC -!- FUNCTION: The terminase large subunit acts as an ATP driven molecular CC motor necessary for viral DNA translocation into empty capsids and as CC an endonuclease that cuts the viral genome to initiate and to end a CC packaging reaction. The terminase lies at a unique vertex of the CC procapsid and is composed of two subunits, a small terminase subunit CC involved in viral DNA recognition (packaging sequence), and a large CC terminase subunit possessing endonucleolytic and ATPase activities. CC Both terminase subunits heterooligomerize and are docked on the portal CC protein to form the packaging machine. The terminase large subunit CC exhibits endonuclease activity and cleaves the viral genome concatemer CC once the capsid is full (headful packaging). Once the capsid is CC packaged with the DNA, the terminase complex is substituted by the CC tail. CC -!- SUBUNIT: Interacts with the terminase small subunit; the active complex CC is composed of a pentamer of terminase large subunits and a dodecamer CC of terminase small subunits. Interacts with the portal protein. CC -!- ACTIVITY REGULATION: Stimulated up to 50 to 100-fold by the terminase CC small subunit. else CC -!- FUNCTION: The terminase large subunit acts as an ATP driven molecular CC motor necessary for viral DNA translocation into empty capsids and as CC an endonuclease that cuts the viral genome to initiate and to end a CC packaging reaction. The terminase lies at a unique vertex of the CC procapsid and is composed of two subunits, a small terminase subunit CC involved in viral DNA recognition (packaging sequence), and a large CC terminase subunit possessing endonucleolytic and ATPase activities. CC Both terminase subunits heterooligomerize and are docked on the portal CC protein to form the packaging machine. The terminase large subunit CC exhibits endonuclease activity and cleaves the viral genome concatemer. CC Once the capsid is packaged with the DNA, the terminase complex is CC substituted by the tail. CC -!- SUBUNIT: Interacts with the terminase small subunit; the active complex CC is probably heterooligomeric. Interacts with the portal protein. end case case or CC -!- COFACTOR: CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420; CC Note=ATPase activity requires 1 Mg(2+) ion per subunit. Nuclease CC activity probably requires 2 Mg(2+) ions per subunit.; end case CC -!- DOMAIN: The N-terminus contains an ATPase domain. The C-terminus CC contains an endonuclease domain. CC -!- SIMILARITY: Belongs to the Tequatrovirus large terminase family. XX DR Pfam; PF03237; Terminase_6; 1; trigger=no DR Pfam; PF17289; Terminase_6C; 1; trigger=no XX KW ATP-binding KW Endonuclease KW Hydrolase case or KW Magnesium KW Metal-binding end case KW Nuclease KW Nucleotide-binding KW Viral genome packaging KW Viral release from host cell XX GO GO:0098009; C:viral terminase, large subunit GO GO:0004519; F:endonuclease activity GO GO:0046872; F:metal ion binding GO GO:0004518; F:nuclease activity GO GO:0051276; P:chromosome organization GO GO:0019073; P:viral DNA genome packaging XX FT From: TERL_BPT4 (P17312) case FT REGION 30..94 FT /note="ssDNA-binding" FT REGION 131..301 FT /note="ATPase activity" FT REGION 328..352 FT /note="Binding to the portal protein" FT REGION 360..559 FT /note="Nuclease activity" end case FT BINDING 138 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT Optional; Group: 2; Condition: Q FT BINDING 143 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT Optional; Group: 2; Condition: Q FT BINDING 202 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT Optional; Group: 2; Condition: R FT MOTIF 251..256 FT /note="Walker B motif" FT Optional; Condition: [FILMV]-[ILV]-[FIY]-[IFLV]-D-E FT MOTIF 285..287 FT /note="ATPase coupling" FT Optional; Condition: T-[ST]-T FT SITE 409 FT /note="Modulates nuclease activity" FT Optional; Condition: D FT ACT_SITE 256 FT /note="For ATPase activity" FT Condition: E case not FT BINDING 401 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="1" FT /ligand_note="catalytic; for nuclease activity" FT Group: 1; Condition: D FT BINDING 401 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="2" FT /ligand_note="catalytic; for nuclease activity" FT Group: 1; Condition: D FT BINDING 458 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="2" FT /ligand_note="catalytic; for nuclease activity" FT Group: 1; Condition: [DE] FT BINDING 542 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="1" FT /ligand_note="catalytic; for nuclease activity" FT Group: 1; Condition: D FT MOTIF 161..167 FT /note="Walker A motif" FT Optional; Condition: [PS]-R-[RQ]-[LV]-G-K-[ST] end case FT From: TERL_BPT5 (Q6QGD2) case FT BINDING 286 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="1" FT /ligand_note="catalytic; for nuclease activity" FT Group: 2; Condition: D FT BINDING 286 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="2" FT /ligand_note="catalytic; for nuclease activity" FT Group: 2; Condition: D FT BINDING 342 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="2" FT /ligand_note="catalytic; for nuclease activity" FT Group: 2; Condition: D FT BINDING 418 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_label="1" FT /ligand_note="catalytic; for nuclease activity" FT Group: 2; Condition: D FT MOTIF 62..68 FT /note="Walker A motif" FT Optional; Condition: [PS]-R-[RQ]-[LV]-G-K-[ST] end case XX Size: 400-650; Related: None; Template: P17312; Q6QGD2; Scope: Viruses Fusion: Nter: None Cter: None Duplicate: None Plasmid: None Comments: None XX # Revision 1.7 2022/11/19 //