AC MF_04144; DC Protein; auto TR HAMAP; MF_04144; -; 1; level=0 XX Names: TERL_LAMBDA XX ID TERL case DE RecName: Full=Terminase, large subunit; DE AltName: Full=DNA-packaging protein; DE AltName: Full=Large terminase protein; DE Includes: DE RecName: Full=Endonuclease; DE EC=3.1.21.4; DE Includes: DE RecName: Full=Helicase; DE EC=3.6.4.12; DE Includes: DE RecName: Full=ATPase; DE EC=3.6.4.-; else DE RecName: Full=Terminase, large subunit; DE AltName: Full=DNA-packaging protein; DE AltName: Full=Large terminase protein; DE Includes: DE RecName: Full=Helicase; DE EC=3.6.4.12; DE Includes: DE RecName: Full=ATPase; DE EC=3.6.4.-; end case 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 from the concetamer to CC initiate and to end the packaging reaction. The terminase lies at a CC unique vertex of the procapsid and is composed of two subunits, a small CC terminase subunit involved in viral DNA recognition (binding to CC packaging sequence cos), and a large terminase subunit possessing CC endonucleolytic, ATPase and helicase activities (DNA maturation and CC packaging). The terminase binds cooperatively with the host factor CC IHFA/IHFB to the cos site at the junction of adjacent viral genomes. CC The endonuclease activity cleaves the viral DNA generating 5'overhangs CC of 12 bp in length. The helicase activity separates the cohesive ends CC generating the single-stranded 'sticky' ends of the mature genome. CC IHFA/IHFB is also necessary for the strand separation activity of the CC terminase. The terminase remains bound to the left end of the genome to CC be packaged, forming a stable DNA-terminase complex. In a reaction CC facilitated by the viral assembly catalyst gpFI, the DNA-terminase CC complex binds to the portal of the procapsid thereby activating the CC translocase activity of the terminase. The terminase packages the viral CC DNA into the procapsid until the next cos site on the concatemer CC reaches the complex. The downstream cos site is then cut generating the CC mature right end of the genome, the heterotrimer undocks from the DNA- CC filled head and remains bound to the left end of concatemer's next CC genome. CC -!- SUBUNIT: Heterotrimer of two small and one large terminase subunits. CC The catalytically competent terminase is composed of a tetramer of CC heterotrimers. The tetramer forms a ring structure large enough to CC encircle duplex DNA. Host IHFA/IHFB induces bending of viral DNA to CC facilitate the assembly of the terminase tetramer of heterotrimers. CC Interacts (via N-terminus) with the terminase small subunit (via C- CC terminus). Interacts (via C-terminus) with the portal protein; this CC interaction allows the packaging of viral DNA. CC -!- DOMAIN: The N-terminus is involved in the formation of the heterotrimer CC with the small subunit. The N-terminus part contains the translocase CC activity involved in DNA packaging. At the N-terminus, there is a high CC affinity ATPase center that is probably needed for the packaging CC activity. The Walker A motif of the ATPase center is responsible for CC interacting with the ATP phosphate and the Q motif governs force CC generation and the interaction with DNA. The C-terminus contains the CC site specific endonuclease (cos-cleavage) and strand separation CC (helicase) activities required for genome maturation. A second ATPase CC catalytic site regulates the genome maturation. The C-terminus very end CC is involved in binding to the procapsid. Contains a basic leucine CC zipper (bZIP) that may be involved in the formation of the terminase. 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 from the concetamer to CC initiate and to end the packaging reaction. The terminase lies at a CC unique vertex of the procapsid and is composed of two subunits, a small CC terminase subunit involved in viral DNA recognition, and a large CC terminase subunit possessing endonucleolytic, ATPase and helicase CC activities (DNA maturation and packaging). The endonuclease activity CC cleaves the viral DNA generating 5'overhangs. The helicase activity CC separates the cohesive ends generating the single-stranded 'sticky' CC ends of the mature genome. The DNA-terminase complex binds to the CC portal of the procapsid thereby activating the translocase activity of CC the terminase. The terminase packages the viral DNA into the procapsid CC until the next concatemer reaches the complex. The downstream site is CC then cut generating the mature right end of the genome, the CC heterotrimer undocks from the DNA-filled head and remains bound to the CC left end of concatemer's next genome. CC -!- SUBUNIT: Interacts (via N-terminus) with the terminase small subunit CC (via C-terminus); the active complex is probably heterooligomeric. CC Interacts (via C-terminus) with the portal protein; this interaction CC allows the packaging of viral DNA. CC -!- DOMAIN: The N-terminus is involved in the formation of the heterotrimer CC with the small subunit. The N-terminus part contains the translocase CC activity involved in DNA packaging. At the N-terminus, there is a high CC affinity ATPase center that is probably needed for the packaging CC activity. The Walker A motif of the ATPase center is responsible for CC interacting with the ATP phosphate and the Q motif governs force CC generation and the interaction with DNA. The C-terminus contains the CC site specific endonuclease (cos-cleavage) and strand separation CC (helicase) activities required for genome maturation. A second ATPase CC catalytic site regulates the genome maturation. The C-terminus very end CC is involved in binding to the procapsid. Contains a basic leucine CC zipper (bZIP) that may be involved in the formation of the terminase. end case case CC -!- COFACTOR: CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420; CC -!- CATALYTIC ACTIVITY: CC Reaction=Endonucleolytic cleavage of DNA to give specific double- CC stranded fragments with terminal 5'-phosphates.; EC=3.1.21.4; end case CC -!- CATALYTIC ACTIVITY: CC Reaction=ATP + H2O = ADP + H(+) + phosphate; Xref=Rhea:RHEA:13065, CC ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, CC ChEBI:CHEBI:43474, ChEBI:CHEBI:456216; CC -!- SUBCELLULAR LOCATION: Host cytoplasm. Note=The terminase lies at a CC unique vertex of the procapsid during viral DNA packaging. CC -!- SIMILARITY: Belongs to the lambdavirus large terminase family. XX DR Pfam; PF05876; Terminase_GpA; 1; trigger=no XX KW ATP-binding KW Endonuclease KW Host cytoplasm KW Hydrolase KW Nuclease KW Nucleotide-binding KW Viral genome packaging KW Viral release from host cell case KW Magnesium KW Metal-binding end case XX GO GO:0098009; C:viral terminase, large subunit GO GO:0005524; F:ATP binding GO GO:0016887; F:ATP hydrolysis activity GO GO:0003678; F:DNA helicase activity GO GO:0004519; F:endonuclease activity GO GO:0019073; P:viral DNA genome packaging GO GO:0009036; F:type II site-specific deoxyribonuclease activity case GO GO:0046872; F:metal ion binding end case XX FT From: TERL_LAMBD (P03708) case FT REGION 1..48 FT /note="Interaction with the terminase small subunit" FT REGION 166..349 FT /note="DNA packaging/ATPase" FT REGION 401..586 FT /note="Endonuclease/helicase" FT REGION 610..641 FT /note="Prohead binding" end case FT BINDING 491..498 FT /ligand="ATP" FT /ligand_id="ChEBI:CHEBI:30616" FT Optional; Condition: G-x(4)-G-K-P FT REGION 588..616 FT /note="Leucine zipper" FT Optional; Condition: L-x(6)-L-x(6)-[IL]-x(6)-L-x(6)-L FT MOTIF 76..83 FT /note="Walker A motif" FT Group: 1; Condition: x(3)-[QR]-x-[GLM]-[FKILY]-[ST] FT MOTIF 174..179 FT /note="Walker B motif" FT Group: 1; Condition: x(4)-D-E FT ACT_SITE 179 FT /note="For ATPase activity" FT Condition: E FT BINDING 401 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="catalytic; for nuclease activity" FT Tag: Magnesium; Condition: D FT SITE 46 FT /note="ATP-binding" FT Condition: Y XX Size: 540-720; Related: None; Template: P03708; Scope: Viruses; Caudoviricetes Fusion: Nter: None Cter: None Duplicate: None Plasmid: None Comments: None XX # Revision 1.9 2022/11/19 //