A0A6G6XGS7 · A0A6G6XGS7_9CAUD
- ProteinTerminase, large subunit
- StatusUniProtKB unreviewed (TrEMBL)
- Organism
- Amino acids605 (go to sequence)
- Protein existenceInferred from homology
- Annotation score4/5
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.
Catalytic activity
- ATP + H2O = ADP + H+ + phosphate
Cofactor
Features
Showing features for active site, binding site.
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | host cell cytoplasm | |
Cellular Component | viral terminase, large subunit | |
Molecular Function | ATP binding | |
Molecular Function | ATP hydrolysis activity | |
Molecular Function | DNA helicase activity | |
Molecular Function | metal ion binding | |
Molecular Function | type II site-specific deoxyribonuclease activity | |
Biological Process | viral DNA genome packaging |
Keywords
- Molecular function
- Biological process
- Ligand
Names & Taxonomy
Protein names
- Recommended nameTerminase, large subunit
- Alternative names
Including 3 domains:
- Recommended nameEndonuclease
- EC number
- Recommended nameHelicase
- EC number
- Recommended nameATPase
- EC number
Gene names
Organism names
- Organism
- Taxonomic lineageViruses > Duplodnaviria > Heunggongvirae > Uroviricota > Caudoviricetes > Herelleviridae > Twortvirinae > Kayvirus > Kayvirus G1
Accessions
- Primary accessionA0A6G6XGS7
Proteomes
Subcellular Location
UniProt Annotation
GO Annotation
Note: The terminase lies at a unique vertex of the procapsid during viral DNA packaging.
Keywords
- Cellular component
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.
Structure
Family & Domains
Features
Showing features for domain, motif.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Domain | 79-287 | Phage terminase large subunit GpA ATPase | ||||
Sequence: AVIKSRQLGLSEMGVMEMVHFADMHSYANAKCLYTFPTNEQMKKFVQSRLNPVLEKEYFRDIVDWDKDSLGFKKIRNSSLFFRTSSKASTVEGVDIDYLSLDEYDRVNLLAESSALESMSSSPFKIVRRWSTPSVPGMGIHKLYQQSDQWYYGHRCQHCDYLNEMSYNDYNPDNLEESGNMLCVNPEGVDEQAKTVQNGSYQFVCQKCG | ||||||
Motif | 82-89 | Walker A motif | ||||
Sequence: KSRQLGLS | ||||||
Motif | 176-181 | Walker B motif | ||||
Sequence: YLSLDE |
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 statusComplete
- Length605
- Mass (Da)70,242
- Last updated2020-08-12 v1
- Checksum1C543C8006ED6614