HAMAP rule MF_04104
General rule information
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| Accession | MF_04104 |
| Dates | 18-OCT-2016 (Created) 1-DEC-2022 (Last updated, Version 9) |
| Name | HOLIN_T4 |
| Scope | Viruses; Caudoviricetes |
| Template | P06808 (HOLIN_BPT4) |
| Triggered by |
Propagated annotation
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Identifier, protein and gene names
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| Identifier |
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| Protein name |
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Comments
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| Function | Accumulates harmlessly in the cytoplasmic membrane until it reaches a critical concentration that triggers the formation of micron-scale pores (holes) causing host cell membrane disruption and endolysin escape into the periplasmic space. Determines the precise timing of host cell lysis. Regulated by specific antiholins that somehow sense superinfections and then delay lysis. Participates with the endolysin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles from the host cell. |
| Subunit | Homomultimer. Heterotetramer composed of 2 holin and 2 antiholin. The holin-antiholin complex binds dsDNA. Interacts (via C-terminus) with antiholin (via C-terminus); this interaction blocks the holin homomultimerization and delays host cell lysis. Interacts (via N-terminus) with the lysis inhibition accessory protein rIII; this interaction stabilizes the holin-antiholin complex thereby resulting in a robust block of the hole formation. |
| Subcellular location | Host cell inner membrane; Single-pass type II membrane protein; Periplasmic side. Note=Classified as a class III holin. |
| Domain | The C-terminus serves, in association with the antiholin, as a DNA sensor for lysis inhibition under superinfection conditions. |
case <FTTag:disulf>
| Ptm | Disulfide bond is required for functionality. |
end case
| Similarity | Belongs to the T4likevirus holin family. |
Keywords
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case <FTTag:disulf>
end case
Host cell inner membrane
Host cell lysis by virus
Host cell membrane
Host membrane
Membrane
Signal-anchor
Transmembrane
Transmembrane helix
Viral release from host cell
Host cell lysis by virus
Host cell membrane
Host membrane
Membrane
Signal-anchor
Transmembrane
Transmembrane helix
Viral release from host cell
Gene Ontology
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GO:0140911; Molecular function: pore-forming activity.
GO:0016020; Cellular component: membrane.
GO:0020002; Cellular component: host cell plasma membrane.
GO:0016020; Cellular component: membrane.
GO:0020002; Cellular component: host cell plasma membrane.
Cross-references
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| Pfam | PF11031; Phage_holin_T; 1; |
Features
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| From: HOLIN_BPT4 (P06808) | ||||||||||||
| Key | From | To | Description | Tag | Condition | FTGroup | ||||||
| TOPO_DOM | Nter | 34 | Cytoplasmic | |||||||||
| TRANSMEM | 35 | 49 | Helical; Signal-anchor for type II membrane protein | |||||||||
| TOPO_DOM | 50 | Cter | Periplasmic | |||||||||
| DISULFID | 175 | 207 | disulf | C-x*-C | ||||||||
Additional information
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| Size range | 188-243 amino acids |
| Related rules | None |
| Fusion | None |