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HAMAP rule MF_04104

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General rule information [?]

Accession MF_04104
Dates 18-OCT-2016 (Created)
1-DEC-2022 (Last updated, Version 9)
Scope(s) Viruses
Template(s) P06808 (HOLIN_BPT4); [ Recover all ]
Triggered by HAMAP; MF_04104 (Get profile general information and statistics)

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier HOLIN
Protein name RecName: Full=Holin;

Comments [?]

FUNCTIONAccumulates 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.
SUBUNITHomomultimer. 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 LOCATIONHost cell inner membrane; Single-pass type II membrane protein; Periplasmic side. Note=Classified as a class III holin.
DOMAINThe C-terminus serves, in association with the antiholin, as a DNA sensor for lysis inhibition under superinfection conditions.
case <FTTag:disulf>
PTMDisulfide bond is required for functionality.
end case
SIMILARITYBelongs to the T4likevirus holin family.

Keywords [?]

Gene Ontology [?]

GO:0140911; Molecular function:pore-forming activity
GO:0016020; Cellular component:membrane
GO:0020002; Cellular component:host cell plasma membrane

Cross-references [?]

Pfam PF11031; Phage_holin_T; 1;

Features [?]

From: HOLIN_BPT4 (P06808)
Key From To Description Tag Condition FTGroup
TOPO_DOM Nter 34 /note="Cytoplasmic"
TRANSMEM 35 49 /note="Helical; Signal-anchor for type II membrane protein"
TOPO_DOM 50 Cter /note="Periplasmic"
DISULFID 175 207 disulf C-x*-C

Additional information [?]

Size range 188-243 amino acids
Related rules None
Fusion Nter: None Cter: None

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