ID   TERS_BPRH5              Reviewed;         145 AA.
AC   P68929; Q38627;
DT   01-FEB-2005, integrated into UniProtKB/Swiss-Prot.
DT   16-SEP-2015, sequence version 2.
DT   03-AUG-2022, entry version 39.
DE   RecName: Full=Terminase small subunit;
DE   AltName: Full=G1P;
GN   Name=1;
OS   Bacillus phage rho15 (Bacteriophage rho-15).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Siphoviridae.
OX   NCBI_TaxID=36451;
OH   NCBI_TaxID=1423; Bacillus subtilis.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8030254; DOI=10.1006/viro.1994.1415;
RA   Chai S., Kruft V., Alonso J.C.;
RT   "Analysis of the Bacillus subtilis bacteriophages SPP1 and SF6 gene 1
RT   product: a protein involved in the initiation of headful packaging.";
RL   Virology 202:930-939(1994).
CC   -!- FUNCTION: The terminase small subunit specifically recognizes the non-
CC       adjacent pacL and pacR packaging subsites and regulates the ATPase
CC       activity of the terminase large subunit. The terminase lies at a unique
CC       vertex of the procapsid and is composed of two subunits, a small
CC       terminase subunit involved in viral DNA recognition (packaging
CC       sequence), and a large terminase subunit possessing endonucleolytic and
CC       ATPase activities. Both terminase subunits heterooligomerize and are
CC       docked on the portal protein to form the packaging machine. The
CC       terminase large subunit exhibits endonuclease activity and cleaves the
CC       viral genome concatemer once the capsid is full (headful packaging).
CC       Once the capsid is packaged with the DNA, the terminase complex is
CC       substituted by neck proteins. {ECO:0000250|UniProtKB:P54307}.
CC   -!- SUBUNIT: Homodecamer. Interacts with the terminase large subunit gp2;
CC       the active complex is probably composed of a one monomer of gp2 and two
CC       or more decamers of gp1. {ECO:0000250|UniProtKB:P54307}.
CC   -!- SIMILARITY: Belongs to the SPP1-like small terminase family.
CC       {ECO:0000305}.
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DR   EMBL; X67298; CAA47712.1; ALT_SEQ; Genomic_DNA.
DR   SMR; P68929; -.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0051276; P:chromosome organization; IEA:InterPro.
DR   Gene3D; 1.10.10.1400; -; 1.
DR   InterPro; IPR038713; Terminase_Gp1_N_sf.
DR   InterPro; IPR005335; Terminase_ssu.
DR   Pfam; PF03592; Terminase_2; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Viral genome packaging; Viral release from host cell.
FT   CHAIN           1..145
FT                   /note="Terminase small subunit"
FT                   /id="PRO_0000077791"
SQ   SEQUENCE   145 AA;  16010 MW;  85C811F726AAEE59 CRC64;
     MKEPKLSPKQ ERFIEEYFIN DMNATKAAIA AGYSKNSASA IGAENLQKPA IRARIDARLK
     EINEKKILQA NEVLEHLTRI ALGQEKEQVL MGIGKGAETK THVEVSAKDR IKALELLGKA
     HAVFTDKQKV ETNQVIIVDD SGDAE