ID   TERS_BPT7               Reviewed;          89 AA.
AC   P03693;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   25-MAY-2022, entry version 70.
DE   RecName: Full=Terminase, small subunit gp18;
DE   AltName: Full=DNA-packaging protein A;
DE   AltName: Full=Gene product 18;
DE            Short=Gp18;
GN   OrderedLocusNames=18;
OS   Escherichia phage T7 (Bacteriophage T7).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Autographiviridae; Studiervirinae; Teseptimavirus.
OX   NCBI_TaxID=10760;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=6864790; DOI=10.1016/s0022-2836(83)80282-4;
RA   Dunn J.J., Studier F.W.;
RT   "Complete nucleotide sequence of bacteriophage T7 DNA and the locations of
RT   T7 genetic elements.";
RL   J. Mol. Biol. 166:477-535(1983).
RN   [2]
RP   SUBUNIT.
RX   PubMed=3036832; DOI=10.1016/s0021-9258(18)47492-3;
RA   White J.H., Richardson C.C.;
RT   "Gene 18 protein of bacteriophage T7. Overproduction, purification, and
RT   characterization.";
RL   J. Biol. Chem. 262:8845-8850(1987).
RN   [3]
RP   FUNCTION.
RX   PubMed=3298244; DOI=10.1016/s0021-9258(18)47493-5;
RA   White J.H., Richardson C.C.;
RT   "Processing of concatemers of bacteriophage T7 DNA in vitro.";
RL   J. Biol. Chem. 262:8851-8860(1987).
CC   -!- FUNCTION: Plays a role in packaging a single copy of genome into the
CC       prohead. The terminase is composed of two subunits (a large and a
CC       small) and the small subunit recognizes the DNA to be encapsidated.
CC       Once the DNA is packaged, the terminase detaches from the connector and
CC       the tail replaces it to finish maturation of the virion.
CC       {ECO:0000269|PubMed:3298244}.
CC   -!- SUBUNIT: Homooctamer (Probable). Interacts with the terminase large
CC       subunit gp19; the active complex is probably heterooligomeric.
CC       {ECO:0000269|PubMed:3036832}.
CC   -!- SIMILARITY: Belongs to the terminase small subunit family.
CC       {ECO:0000305}.
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DR   EMBL; V01146; CAA24437.1; -; Genomic_DNA.
DR   PIR; A04315; JVBPA7.
DR   RefSeq; NP_042007.1; NC_001604.1.
DR   GeneID; 1261042; -.
DR   KEGG; vg:1261042; -.
DR   Proteomes; UP000000840; Genome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   InterPro; IPR024345; DNA_matur_Phage_T7-like.
DR   Pfam; PF11123; DNA_Packaging_2; 1.
PE   1: Evidence at protein level;
KW   DNA-binding; Reference proteome; Viral genome packaging;
KW   Viral release from host cell.
FT   CHAIN           1..89
FT                   /note="Terminase, small subunit gp18"
FT                   /id="PRO_0000106535"
SQ   SEQUENCE   89 AA;  10146 MW;  344B03EC22B42145 CRC64;
     MEKDKSLITF LEMLDTAMAQ RMLADLSDHE RRSPQLYNAI NKLLDRHKFQ IGKLQPDVHI
     LGGLAGALEE YKEKVGDNGL TDDDIYTLQ