A0A6G6XGS7 · A0A6G6XGS7_9CAUD

Function

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 from the concetamer to initiate and to end the 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, and a large terminase subunit possessing endonucleolytic, ATPase and helicase activities (DNA maturation and packaging). The endonuclease activity cleaves the viral DNA generating 5'overhangs. The helicase activity separates the cohesive ends generating the single-stranded 'sticky' ends of the mature genome. The DNA-terminase complex binds to the portal of the procapsid thereby activating the translocase activity of the terminase. The terminase packages the viral DNA into the procapsid until the next concatemer reaches the complex. The downstream site is then cut generating the mature right end of the genome, the heterotrimer undocks from the DNA-filled head and remains bound to the left end of concatemer's next genome.

Caution

Lacks conserved residue(s) required for the propagation of feature annotation.

Catalytic activity

Cofactor

Mg2+ (UniProtKB | Rhea| CHEBI:18420 )

Features

Showing features for active site, binding site.

TypeIDPosition(s)Description
Active site181For ATPase activity
Binding site390Mg2+ (UniProtKB | ChEBI); catalytic; for nuclease activity

GO annotations

AspectTerm
Cellular Componenthost cell cytoplasm
Cellular Componentviral terminase, large subunit
Molecular FunctionATP binding
Molecular FunctionATP hydrolysis activity
Molecular FunctionDNA helicase activity
Molecular Functionmetal ion binding
Molecular Functiontype II site-specific deoxyribonuclease activity
Biological Processviral DNA genome packaging

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Terminase, large subunit
  • Alternative names
    • DNA-packaging protein
    • Large terminase protein

Including 3 domains:

  • Recommended name
    Endonuclease
  • EC number
  • Recommended name
    Helicase
  • EC number
  • Recommended name
    ATPase
  • EC number

Gene names

    • ORF names
      SB1M9832_gp120

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Viruses > Duplodnaviria > Heunggongvirae > Uroviricota > Caudoviricetes > Herelleviridae > Twortvirinae > Kayvirus > Kayvirus G1

Accessions

  • Primary accession
    A0A6G6XGS7

Proteomes

Subcellular Location

Host cytoplasm
Note: The terminase lies at a unique vertex of the procapsid during viral DNA packaging.

Keywords

Interaction

Subunit

Interacts (via N-terminus) with the terminase small subunit (via C-terminus); the active complex is probably heterooligomeric. Interacts (via C-terminus) with the portal protein; this interaction allows the packaging of viral DNA.

Family & Domains

Features

Showing features for domain, motif.

TypeIDPosition(s)Description
Domain79-287Phage terminase large subunit GpA ATPase
Motif82-89Walker A motif
Motif176-181Walker B motif

Domain

The N-terminus is involved in the formation of the heterotrimer with the small subunit. The N-terminus part contains the translocase activity involved in DNA packaging. At the N-terminus, there is a high affinity ATPase center that is probably needed for the packaging activity. The Walker A motif of the ATPase center is responsible for interacting with the ATP phosphate and the Q motif governs force generation and the interaction with DNA. The C-terminus contains the site specific endonuclease (cos-cleavage) and strand separation (helicase) activities required for genome maturation. A second ATPase catalytic site regulates the genome maturation. The C-terminus very end is involved in binding to the procapsid. Contains a basic leucine zipper (bZIP) that may be involved in the formation of the terminase.

Sequence similarities

Belongs to the lambdavirus large terminase family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    605
  • Mass (Da)
    70,242
  • Last updated
    2020-08-12 v1
  • Checksum
    1C543C8006ED6614
MDGKELIKIAQETFQTEKITREQIDHIINMLNPSTYMLKYHTLRGHPITFSIPNRDRSKAQAHRPWQTRIVNDTHPNKAVIKSRQLGLSEMGVMEMVHFADMHSYANAKCLYTFPTNEQMKKFVQSRLNPVLEKEYFRDIVDWDKDSLGFKKIRNSSLFFRTSSKASTVEGVDIDYLSLDEYDRVNLLAESSALESMSSSPFKIVRRWSTPSVPGMGIHKLYQQSDQWYYGHRCQHCDYLNEMSYNDYNPDNLEESGNMLCVNPEGVDEQAKTVQNGSYQFVCQKCGKPLDRWYNGEWHCKYPERTKGNKGVRGYLITQMNAVWISADELKEKEMNTESKQAFYNYILGYPFEDVKLRVNEEDVYGNKSPIAETQLMKRDRYSHIAIGIDWGNTHWITVHGMLPNGKVDLIRLFSVKKMTRPDLVEADLEKIIWEISKYDPDIIIADNGDSGNNVLKLINHFGKDKVFGCTYKSSPKSTGQLRPEFNENNNRVTVDKLMQNKRYVQALKTKDISVYSTVDDDLKTFLKHWQNVVIMDEEDEKTGEMYQVIKRKGDDHYAQASVYAYIGLTRIKELLKEGNGTSFGSTFVSTDYNQEGNKQFYFDE

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
MN336263
EMBL· GenBank· DDBJ
QIG56776.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

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