ID   HOLIN_BPT1              Reviewed;          71 AA.
AC   Q6XQ99;
DT   14-MAY-2014, integrated into UniProtKB/Swiss-Prot.
DT   05-JUL-2004, sequence version 1.
DT   12-AUG-2020, entry version 39.
DE   RecName: Full=Holin {ECO:0000305};
DE   AltName: Full=Pinholin {ECO:0000305};
GN   ORFNames=13;
OS   Escherichia phage T1 (Bacteriophage T1).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Drexlerviridae; Tunavirinae; Tunavirus.
OX   NCBI_TaxID=1921008;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=14972552; DOI=10.1016/j.virol.2003.09.020;
RA   Roberts M.D., Martin N.L., Kropinski A.M.;
RT   "The genome and proteome of coliphage T1.";
RL   Virology 318:245-266(2004).
CC   -!- FUNCTION: Accumulates harmlessly in the cytoplasmic membrane until it
CC       reaches a critical concentration that triggers the formation of
CC       nanometer-scale pores (pinholes) causing host cell membrane
CC       depolarization and endolysin refolding and release into the periplasmic
CC       space (By similarity). Once the pinholin has permeabilized the host
CC       cell membrane, the SAR-endolysin is released into the periplasm and
CC       breaks down the peptidoglycan layer (By similarity). Determines the
CC       precise timing of host cell lysis. Participates with the SAR-endolysin
CC       and the U-spanin protein in the sequential events which lead to the
CC       programmed host cell lysis releasing the mature viral particles from
CC       the host cell (By similarity). {ECO:0000250|UniProtKB:Q7Y2C1}.
CC   -!- SUBUNIT: Homomultimer. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Host cell inner membrane
CC       {ECO:0000250|UniProtKB:P03705}; Single-pass type II membrane protein
CC       {ECO:0000255}.
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DR   EMBL; AY216660; AAP49986.1; -; Genomic_DNA.
DR   RefSeq; YP_003932.1; NC_005833.1.
DR   SMR; Q6XQ99; -.
DR   TCDB; 1.E.37.1.1; the phage t1 holin (t1 holin) family.
DR   GeneID; 2772978; -.
DR   KEGG; vg:2772978; -.
DR   Proteomes; UP000001156; Genome.
DR   GO; GO:0020002; C:host cell plasma membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0019835; P:cytolysis; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Cytolysis; Host cell inner membrane; Host cell lysis by virus;
KW   Host cell membrane; Host membrane; Membrane; Reference proteome;
KW   Signal-anchor; Transmembrane; Transmembrane helix;
KW   Viral release from host cell.
FT   CHAIN           1..71
FT                   /note="Holin"
FT                   /id="PRO_0000429259"
FT   TOPO_DOM        1..24
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000305"
FT   TRANSMEM        25..45
FT                   /note="Helical; Signal-anchor for type II membrane protein"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        46..71
FT                   /note="Periplasmic"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   71 AA;  7578 MW;  19E45AE35DBF928F CRC64;
     MKEFLTAATS STGGASLVGA ATGQLYIAGA TFICFLLFGA WGAYWKYRDS KAIQEALNDG
     DLNKALKIRG R