ID   HOLIN_BPHC1             Reviewed;          78 AA.
AC   P51727;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   23-FEB-2022, entry version 77.
DE   RecName: Full=Holin {ECO:0000305};
DE   AltName: Full=Pinholin {ECO:0000305};
GN   Name=hol;
OS   Haemophilus phage HP1 (strain HP1c1) (Bacteriophage HP1).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Myoviridae; Peduovirinae; Hpunavirus.
OX   NCBI_TaxID=1289570;
OH   NCBI_TaxID=727; Haemophilus influenzae.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=6098523; DOI=10.1016/0378-1119(84)90208-7;
RA   Benjamin R.C., Fitzmaurice W.P., Huang P.C., Scocca J.J.;
RT   "Nucleotide sequence of cloned DNA segments of the Haemophilus influenzae
RT   bacteriophage HP1c1.";
RL   Gene 31:173-185(1984).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=8710508; DOI=10.1093/nar/24.12.2360;
RA   Esposito D., Fitzmaurice W.P., Benjamin R.C., Goodman S.D., Waldman A.S.,
RA   Scocca J.J.;
RT   "The complete nucleotide sequence of bacteriophage HP1 DNA.";
RL   Nucleic Acids Res. 24:2360-2368(1996).
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   -!- SUBCELLULAR LOCATION: Host cell inner membrane
CC       {ECO:0000250|UniProtKB:P03705}; Multi-pass membrane protein
CC       {ECO:0000255}.
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DR   EMBL; U24159; AAB09210.1; -; Genomic_DNA.
DR   PIR; S69531; S69531.
DR   RefSeq; NP_043494.1; NC_001697.1.
DR   SMR; P51727; -.
DR   TCDB; 1.E.7.1.1; the hp1 holin (hp1 holin) family.
DR   GeneID; 1261118; -.
DR   KEGG; vg:1261118; -.
DR   Proteomes; UP000001713; 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.
DR   InterPro; IPR032118; Phage_holin_HP1.
DR   Pfam; PF16080; Phage_holin_2_3; 1.
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   Transmembrane; Transmembrane helix; Viral release from host cell.
FT   CHAIN           1..78
FT                   /note="Holin"
FT                   /id="PRO_0000165307"
FT   TOPO_DOM        1..6
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        7..23
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        24..29
FT                   /note="Periplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        30..46
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        47..78
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   78 AA;  8694 MW;  3FC0596BE0AE4FED CRC64;
     MNSKIDSAIP FIGSLTALIS GYSLHEWASL FGILFGAVSV WIAYRKYKED VQARKDELAY
     KMLVAKIEAK KLGIAIDE