ID   HOLIN_BPB03             Reviewed;         132 AA.
AC   Q37895;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   29-SEP-2021, entry version 71.
DE   RecName: Full=Antiholin {ECO:0000250|UniProtKB:P03705};
DE   AltName: Full=Gene product 14;
DE            Short=gp14;
DE   AltName: Full=Protein p14;
DE   Includes:
DE     RecName: Full=Holin {ECO:0000250|UniProtKB:P03705};
GN   Name=14;
OS   Bacillus phage B103 (Bacteriophage B103).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Salasmaviridae; Picovirinae; Beecentumtrevirus.
OX   NCBI_TaxID=10778;
OH   NCBI_TaxID=1423; Bacillus subtilis.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=9358052; DOI=10.1016/s0378-1119(97)00363-6;
RA   Pecenkova T., Benes V., Paces J., Vlcek C., Paces V.;
RT   "Bacteriophage B103: complete DNA sequence of its genome and relationship
RT   to other Bacillus phages.";
RL   Gene 199:157-163(1997).
CC   -!- FUNCTION: [Isoform Holin]: Accumulates harmlessly in the cytoplasmic
CC       membrane until it reaches a critical concentration that triggers the
CC       formation of micron-scale pores (holes) causing host cell membrane
CC       disruption and endolysin escape into the periplasmic space (By
CC       similarity). Determines the precise timing of host cell lysis (By
CC       similarity). Participates with the endolysin and spanin proteins in the
CC       sequential events which lead to the programmed host cell lysis
CC       releasing the mature viral particles from the host cell (By
CC       similarity). {ECO:0000250|UniProtKB:P03705}.
CC   -!- FUNCTION: [Isoform Antiholin]: Counteracts the aggregation of the holin
CC       molecules and thus of pore formation. {ECO:0000250|UniProtKB:P03705}.
CC   -!- SUBUNIT: [Isoform Holin]: Homomultimer. Interacts with isoform
CC       Antiholin; this interaction blocks the holin homomultimerization and
CC       delays host cell lysis. {ECO:0000250|UniProtKB:P03705}.
CC   -!- SUBCELLULAR LOCATION: Host cell inner membrane
CC       {ECO:0000250|UniProtKB:P03705}; Multi-pass membrane protein
CC       {ECO:0000250|UniProtKB:P03705}. Note=Classified as a class I holin.
CC       {ECO:0000305}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative initiation; Named isoforms=2;
CC       Name=Antiholin {ECO:0000250|UniProtKB:P03705};
CC         IsoId=Q37895-1; Sequence=Displayed;
CC       Name=Holin {ECO:0000250|UniProtKB:P03705};
CC         IsoId=Q37895-2; Sequence=VSP_058248;
CC   -!- DOMAIN: Isoform Holin has 3 transmembrane regions whereas isoform
CC       Antiholin lacks the first transmembrane region.
CC       {ECO:0000250|UniProtKB:P03705}.
CC   -!- DOMAIN: The C-terminus acts as a cytoplasmic regulatory region.
CC       {ECO:0000250|UniProtKB:P03705}.
CC   -!- SIMILARITY: Belongs to the bacteriophage holin family. phi29likevirus
CC       holin subfamily. {ECO:0000305}.
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DR   EMBL; X99260; CAA67662.1; -; Genomic_DNA.
DR   RefSeq; NP_690648.1; NC_004165.1. [Q37895-1]
DR   TCDB; 1.E.10.1.4; the bacillus subtilis Phi29 holin (Phi29 holin) family.
DR   GeneID; 955368; -.
DR   KEGG; vg:955368; -.
DR   Proteomes; UP000000971; 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; IPR006480; Phage_holin_4_1.
DR   Pfam; PF05105; Phage_holin_4_1; 1.
DR   TIGRFAMs; TIGR01593; holin_tox_secr; 1.
PE   3: Inferred from homology;
KW   Alternative initiation; Cytolysis; Host cell inner membrane;
KW   Host cell lysis by virus; Host cell membrane; Host membrane; Late protein;
KW   Membrane; Transmembrane; Transmembrane helix; Viral release from host cell.
FT   CHAIN           1..132
FT                   /note="Antiholin"
FT                   /id="PRO_0000106597"
FT   TOPO_DOM        1..61
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
FT   TRANSMEM        62..80
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        81..85
FT                   /note="Periplasmic"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
FT   TRANSMEM        86..107
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        108..132
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
FT   VAR_SEQ         1..3
FT                   /note="Missing (in isoform Holin)"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
FT                   /id="VSP_058248"
FT   TOPO_DOM        Q37895-2:1..16
FT                   /note="Periplasmic"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
FT   TRANSMEM        Q37895-2:17..38
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        Q37895-2:39..58
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000250|UniProtKB:P03705"
SQ   SEQUENCE   132 AA;  15117 MW;  D6FE785DA5AAB6BF CRC64;
     MMNMIEWTKH VLESDDTKLI YWLTLLMVCM IVDTILGIVI ARINPKEKFS SFKMKTGILI
     KVSEMIIALL AVPFALPFPA GLPLLYTVYT ALCVSEMYSI FGHLRVVDDK SNFLSIIEGF
     FKQTYRKDKG DK