ID   IPI1_BPT4               Reviewed;          95 AA.
AC   P03718;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   13-AUG-1987, sequence version 1.
DT   02-JUN-2021, entry version 91.
DE   RecName: Full=Internal protein I;
DE            Short=IpI;
DE   Flags: Precursor;
GN   Name=ipi1; Synonyms=ipi;
OS   Enterobacteria phage T4 (Bacteriophage T4).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Myoviridae; Tevenvirinae; Tequatrovirus.
OX   NCBI_TaxID=10665;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=4057254; DOI=10.1016/0022-2836(85)90071-3;
RA   Broida J., Abelson J.;
RT   "Sequence organization and control of transcription in the bacteriophage T4
RT   tRNA region.";
RL   J. Mol. Biol. 185:545-563(1985).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=12626685; DOI=10.1128/mmbr.67.1.86-156.2003;
RA   Miller E.S., Kutter E., Mosig G., Arisaka F., Kunisawa T., Ruger W.;
RT   "Bacteriophage T4 genome.";
RL   Microbiol. Mol. Biol. Rev. 67:86-156(2003).
RN   [3]
RP   PROTEIN SEQUENCE OF 16-95.
RX   PubMed=845944; DOI=10.1016/s0022-2836(77)80104-6;
RA   Isobe T., Black L.W., Tsugita A.;
RT   "Complete aimino acid sequence of bacteriophage T4 internal protein I and
RT   its cleavage site on virus maturation.";
RL   J. Mol. Biol. 110:165-177(1977).
CC   -!- FUNCTION: Internal protein I is one of four proteins in a complex that
CC       functions in bacteriophage head maturation.
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DR   EMBL; X03016; CAA26803.1; -; Genomic_DNA.
DR   EMBL; AF158101; AAD42585.1; -; Genomic_DNA.
DR   PIR; A92919; HIBP14.
DR   PIR; S48006; S48006.
DR   RefSeq; NP_049749.1; NC_000866.4.
DR   PDB; 2JUB; NMR; -; A=20-95.
DR   PDBsum; 2JUB; -.
DR   BMRB; P03718; -.
DR   SMR; P03718; -.
DR   GeneID; 1258561; -.
DR   KEGG; vg:1258561; -.
DR   EvolutionaryTrace; P03718; -.
DR   Proteomes; UP000009087; Genome.
DR   GO; GO:0032067; F:type IV site-specific deoxyribonuclease activity; IMP:CACAO.
DR   Gene3D; 2.20.25.370; -; 1.
DR   InterPro; IPR024373; Phage_T4_IpI.
DR   InterPro; IPR038569; Phage_T4_IpI_C_sf.
DR   Pfam; PF11634; IPI_T4; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Reference proteome.
FT   PROPEP          1..19
FT                   /id="PRO_0000003338"
FT   CHAIN           20..95
FT                   /note="Internal protein I"
FT                   /id="PRO_0000003339"
FT   SITE            19..20
FT                   /note="Cleavage; by prohead core protease GP21"
FT                   /evidence="ECO:0000269|PubMed:845944"
FT   HELIX           22..29
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          31..33
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          35..39
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   TURN            41..43
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          46..49
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   TURN            53..56
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          58..61
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          63..71
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          75..77
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   STRAND          80..83
FT                   /evidence="ECO:0007829|PDB:2JUB"
FT   HELIX           84..94
FT                   /evidence="ECO:0007829|PDB:2JUB"
SQ   SEQUENCE   95 AA;  10177 MW;  486230F2F8949A7B CRC64;
     MKTFKEFTST TTPVSTITEA TLTSEVIKAN KGREGKPMIS LVDGEEIKGT VYLGDGWSAK
     KDGATIVISP AEETALFKAK HISAAHLKII AKNLL