ID   G3P_BPI22               Reviewed;         434 AA.
AC   P15415;
DT   01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1990, sequence version 1.
DT   02-JUN-2021, entry version 98.
DE   RecName: Full=Attachment protein G3P;
DE   AltName: Full=Gene 3 protein;
DE            Short=G3P;
DE   AltName: Full=Minor coat protein;
DE   Flags: Precursor;
GN   Name=III;
OS   Enterobacteria phage I2-2 (Bacteriophage I2-2).
OC   Viruses; Monodnaviria; Loebvirae; Hofneiviricota; Faserviricetes;
OC   Tubulavirales; Inoviridae; Lineavirus.
OX   NCBI_TaxID=10869;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1556749; DOI=10.1007/bf00182391;
RA   Stassen A.P., Schonmakers E.F., Yu M., Schoenmakers J.G., Konings R.N.H.;
RT   "Nucleotide sequence of the genome of the filamentous bacteriophage I2-2:
RT   module evolution of the filamentous phage genome.";
RL   J. Mol. Evol. 34:141-152(1992).
CC   -!- FUNCTION: Plays essential roles both in the penetration of the viral
CC       genome into the bacterial host via pilus retraction and in the
CC       extrusion process. During the initial step of infection, G3P mediates
CC       adsorption of the phage to its primary receptor, the tip of host I-
CC       pilus. Subsequent interaction with the host entry receptor tolA induces
CC       penetration of the viral DNA into the host cytoplasm. In the extrusion
CC       process, G3P mediates the release of the membrane-anchored virion from
CC       the cell via its C-terminal domain (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Interacts with G6P; this interaction is required for proper
CC       integration of G3P and G6P into the virion. Interacts with G8P (By
CC       similarity). Interacts with host tolA (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Virion {ECO:0000305}. Host membrane
CC       {ECO:0000305}; Single-pass type I membrane protein {ECO:0000305}.
CC       Note=Prior to assembly, G3P is found associated with the bacterial host
CC       inner membrane. There are about five copies of this protein per mature
CC       phage that are located on the head side of the filamentous virion.
CC   -!- SIMILARITY: Belongs to the inovirus G3P protein family. {ECO:0000305}.
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DR   EMBL; X14336; CAA32518.1; -; Genomic_DNA.
DR   PIR; S08091; S08091.
DR   RefSeq; NP_039621.1; NC_001332.1.
DR   SMR; P15415; -.
DR   GeneID; 1260723; -.
DR   KEGG; vg:1260723; -.
DR   Proteomes; UP000000373; Genome.
DR   GO; GO:0033644; C:host cell membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0019028; C:viral capsid; IEA:UniProtKB-KW.
DR   GO; GO:0098671; P:adhesion receptor-mediated virion attachment to host cell; IEA:UniProtKB-KW.
DR   GO; GO:0098670; P:entry receptor-mediated virion attachment to host cell; IEA:UniProtKB-KW.
DR   GO; GO:0039667; P:viral entry into host cell via pilus retraction; IEA:UniProtKB-KW.
DR   GO; GO:0099045; P:viral extrusion; IEA:UniProtKB-KW.
DR   GO; GO:0039666; P:virion attachment to host cell pilus; IEA:UniProtKB-KW.
DR   InterPro; IPR008021; Attachment_G3P_N.
DR   InterPro; IPR036200; Attachment_G3P_N_sf.
DR   Pfam; PF05357; Phage_Coat_A; 1.
DR   SUPFAM; SSF50176; SSF50176; 1.
PE   3: Inferred from homology;
KW   Capsid protein; Host membrane; Host-virus interaction; Membrane;
KW   Reference proteome; Signal; Transmembrane; Transmembrane helix;
KW   Viral attachment to host adhesion receptor; Viral attachment to host cell;
KW   Viral attachment to host cell pilus;
KW   Viral attachment to host entry receptor; Viral extrusion;
KW   Viral penetration into host cytoplasm;
KW   Viral penetration into host cytoplasm via pilus retraction;
KW   Viral release from host cell; Virion; Virus entry into host cell.
FT   SIGNAL          1..19
FT   CHAIN           20..434
FT                   /note="Attachment protein G3P"
FT                   /id="PRO_0000003290"
FT   TRANSMEM        408..429
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   REGION          118..137
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          191..260
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          272..311
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        235..260
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        283..300
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   434 AA;  45426 MW;  16156BBDC81F7750 CRC64;
     MKRKIIAISL FLYIPLSNAD NWESITKSYY TGFAMSKTVE SKDQDGKTVR KEVITQADLT
     TACNDAKASA QDVFNQMKLT FSGIWPDSQF RLVTGDTCVY NGSPSEKTES WSIRAQVEGD
     MQRSVPDEEP SEQTPEEICE AKPPIDGVFN NVSKGDEGGF YINYNGCEYE ATGVTVCQND
     GTVCASSAWK PTGYVPESGE SSSSPVKDGD TGGTGEGGSD TGGDTGGGDT GGGSTGGDTG
     GSTGGGSTGG GSTGGSTGKS LTKEDVTAAI HDASPSIGDA VKDSLTEDND QNDNQKKADE
     QSAKASASVS DAISDGMRGV GNFVDDLGGE SSQYGIGNSE MDLSVSLAKG QLGIDLEGHG
     SAWESFLNDG ALRPSIPSGH GCTDFVMFQG SVYQLDIGCD KLGDIKSVLS WVMYCLTFWY
     VFQSATSLLR KGEQ