ID   VG05_BPP21              Reviewed;         501 AA.
AC   P36273; Q38454;
DT   01-JUN-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1994, sequence version 1.
DT   03-AUG-2022, entry version 82.
DE   RecName: Full=Head-tail preconnector protein GP5;
DE            EC=3.4.21.-;
DE   AltName: Full=Putative peptidase GP5;
DE   Contains:
DE     RecName: Full=Scaffold protein GP6;
DE     AltName: Full=Head protein GP6;
GN   Name=5;
GN   and
GN   Name=6;
OS   Enterobacteria phage P21 (Bacteriophage 21) (Bacteriophage P21).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Siphoviridae; Lambdavirus.
OX   NCBI_TaxID=10711;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8472949; DOI=10.1016/0378-1119(93)90583-o;
RA   Smith M.P., Feiss M.;
RT   "Sequence analysis of the phage 21 genes for prohead assembly and head
RT   completion.";
RL   Gene 126:1-7(1993).
CC   -!- FUNCTION: Scaffold protein GP6 forms the scaffold for capsid assembly
CC       and is required for binding of the 5 and 4 protein products. It is
CC       subsequently lost from the head during maturation.
CC   -!- SIMILARITY: Belongs to the peptidase S49 family. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAA32344.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; M81255; AAA32343.1; -; Genomic_DNA.
DR   EMBL; M81255; AAA32344.1; ALT_INIT; Genomic_DNA.
DR   SMR; P36273; -.
DR   MEROPS; S49.003; -.
DR   GO; GO:0008236; F:serine-type peptidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   CDD; cd07022; S49_Sppa_36K_type; 1.
DR   InterPro; IPR029045; ClpP/crotonase-like_dom_sf.
DR   InterPro; IPR002142; Peptidase_S49.
DR   InterPro; IPR033855; Protein_C.
DR   Pfam; PF01343; Peptidase_S49; 1.
DR   SUPFAM; SSF52096; SSF52096; 1.
PE   3: Inferred from homology;
KW   Hydrolase; Protease; Repeat; Serine protease; Viral capsid assembly;
KW   Viral release from host cell.
FT   CHAIN           1..501
FT                   /note="Head-tail preconnector protein GP5"
FT                   /id="PRO_0000027360"
FT   CHAIN           302..501
FT                   /note="Scaffold protein GP6"
FT                   /id="PRO_0000027361"
FT   REPEAT          321..358
FT                   /note="TRI 1"
FT   REPEAT          371..417
FT                   /note="TRI 2"
FT   REPEAT          418..455
FT                   /note="TRI 3"
FT   REGION          321..455
FT                   /note="3 X 38 AA repeats"
FT   ACT_SITE        162
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        214
FT                   /note="Proton donor/acceptor"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   501 AA;  52441 MW;  1C7C4A450A09FCCF CRC64;
     MRRNLSHIIA AAFNEPLLLE PAYARVFFCA LGREMGAASL SVPQQQVQFD APGMLAETDE
     YMAGGKRPAR VYRVVNGIAV LPVTGTLVHR LGGMRPFSGM TGYDGIVACL QQAMADSQVR
     GVLLDIDSPG GQAAGAFDCA DMIYRLRQQK PVWALCNDTA CSAAMLLASA CSRRLVTQTS
     RIGSIGVMMS HVSYAGHLAQ AGVDITLIYS GAHKVDGNQF EALPAEVRQD MQQRIDAARR
     MFAEKVAMYT GLSVDAVTGT EAAVFEGQSG IEAGLADELI NASDAISVMA TALNSNVRGG
     TMPQLTATEA AAQENQRVMG ILTCQEAKGR EQLATMLAGQ QGMSVEQARA ILAAAAPQQP
     VASTQSEADR IMVCEEANGR EQLAATLAAM PEMTVEKARP ILAASPQADA GPSLRDQIMA
     LDEAKGAEAQ AEQLAACPGM TVESARAVLA AGSGKAEPVS ASTTAMFEHF MANHSPAAVQ
     GGVAQTSADG DADVKMLMAM P