ID   PORTL_BPMU              Reviewed;         512 AA.
AC   Q9T1W5;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   23-FEB-2022, entry version 61.
DE   RecName: Full=Portal protein;
DE   AltName: Full=Gene product 29;
DE            Short=gp29;
DE   AltName: Full=Gene product H;
DE            Short=gpH;
DE   AltName: Full=Head-tail connector;
GN   Name=H; OrderedLocusNames=Mup29;
OS   Escherichia phage Mu (Bacteriophage Mu).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Myoviridae; Muvirus.
OX   NCBI_TaxID=10677;
OH   NCBI_TaxID=543; Enterobacteriaceae.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], AND FUNCTION.
RX   PubMed=11922669; DOI=10.1006/jmbi.2002.5437;
RA   Morgan G.J., Hatfull G.F., Casjens S., Hendrix R.W.;
RT   "Bacteriophage Mu genome sequence: analysis and comparison with Mu-like
RT   prophages in Haemophilus, Neisseria and Deinococcus.";
RL   J. Mol. Biol. 317:337-359(2002).
RN   [2]
RP   FUNCTION, SUBUNIT, SUBCELLULAR LOCATION, AND CLEAVAGE OF C-TERMINUS.
RX   PubMed=8599204; DOI=10.1006/viro.1996.0107;
RA   Grimaud R.;
RT   "Bacteriophage Mu head assembly.";
RL   Virology 217:200-210(1996).
RN   [3]
RP   FUNCTION.
RX   PubMed=9495752; DOI=10.1128/jb.180.5.1148-1153.1998;
RA   Grimaud R., Toussaint A.;
RT   "Assembly of both the head and tail of bacteriophage Mu is blocked in
RT   Escherichia coli groEL and groES mutants.";
RL   J. Bacteriol. 180:1148-1153(1998).
RN   [4]
RP   INDUCTION.
RX   PubMed=8293968; DOI=10.1093/genetics/135.3.619;
RA   Chiang L.W., Howe M.M.;
RT   "Mutational analysis of a C-dependent late promoter of bacteriophage Mu.";
RL   Genetics 135:619-629(1993).
CC   -!- FUNCTION: Forms the portal vertex of the capsid. This portal plays
CC       critical roles in head assembly, genome packaging, neck/tail
CC       attachment, and genome ejection. The portal protein multimerizes as a
CC       single ring-shaped homododecamer arranged around a central channel.
CC       Binds to the terminase subunits to form the packaging machine. Acts as
CC       a linker between the capsid and tail. Required for attachment of the
CC       neck proteins to the capsid. {ECO:0000305|PubMed:11922669,
CC       ECO:0000305|PubMed:8599204, ECO:0000305|PubMed:9495752}.
CC   -!- SUBUNIT: Homododecamer (Probable). Part of the immature prohead
CC       complex. Might interact with viral I protease; this interaction gives
CC       rise to an early 25S initiator complex (Probable). The scaffolding
CC       protein Z and the capsid protein T should then be added to this
CC       initiator complex to yield the immature prohead (Probable). Host GroEL
CC       and GroES are also essential for the correct assembly of viral head and
CC       tail. {ECO:0000269|PubMed:8599204, ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Virion {ECO:0000269|PubMed:8599204}. Host
CC       cytoplasm {ECO:0000305|PubMed:8599204}. Note=Located at a unique 5-fold
CC       vertex of the icosahedral capsid.
CC   -!- INDUCTION: Expressed in the late phase of the viral replicative cycle.
CC       Expression of late genes is activated by the viral late transcription
CC       activator C. {ECO:0000269|PubMed:8293968}.
CC   -!- PTM: Cleavage by the viral I protease yields a C-terminally cleaved
CC       portal protein competent for DNA packaging and procpasid maturation.
CC       {ECO:0000269|PubMed:8599204}.
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DR   EMBL; AF083977; AAF01107.1; -; Genomic_DNA.
DR   RefSeq; NP_050633.1; NC_000929.1.
DR   TCDB; 1.W.9.1.1; the escherichia coli mu phage portal protein 9 (ppp9) family.
DR   GeneID; 2636304; -.
DR   KEGG; vg:2636304; -.
DR   Proteomes; UP000002611; Genome.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0019028; C:viral capsid; IEA:UniProtKB-KW.
DR   GO; GO:0099000; P:viral genome ejection through host cell envelope, contractile tail mechanism; IEA:UniProtKB-KW.
DR   InterPro; IPR009279; DUF935.
DR   Pfam; PF06074; DUF935; 1.
PE   1: Evidence at protein level;
KW   Capsid protein; Host cytoplasm; Late protein; Reference proteome;
KW   Viral capsid assembly; Viral contractile tail ejection system;
KW   Viral genome ejection through host cell envelope; Viral genome packaging;
KW   Viral penetration into host cytoplasm; Viral release from host cell;
KW   Virion; Virus entry into host cell.
FT   CHAIN           1..512
FT                   /note="Portal protein"
FT                   /id="PRO_0000077824"
SQ   SEQUENCE   512 AA;  56888 MW;  35E1B99373DCFC36 CRC64;
     MGRILDISGQ PFDFDDEMQS RSDELAMVMK RTQEHPSSGV TPNRAAQMLR DAERGDLTAQ
     ADLAFDMEEK DTHLFSELSK RRLAIQALEW RIAPARDASA QEKKDADMLN EYLHDAAWFE
     DALFDAGDAI LKGYSMQEIE WGWLGKMRVP VALHHRDPAL FCANPDNLNE LRLRDASYHG
     LELQPFGWFM HRAKSRTGYV GTNGLVRTLI WPFIFKNYSV RDFAEFLEIY GLPMRVGKYP
     TGSTNREKAT LMQAVMDIGR RAGGIIPMGM TLDFQSAADG QSDPFMAMIG WAEKAISKAI
     LGGTLTTEAG DKGARSLGEV HDEVRREIRN ADVGQLARSI NRDLIYPLLA LNSDSTIDIN
     RLPGIVFDTS EAGDITALSD AIPKLAAGMR IPVSWIQEKL HIPQPVGDEA VFTIQPVVPD
     NGSQKEAALS AEDIPQEDDI DRMGVSPEDW QRSVDPLLKP VIFSVLKDGP EAAMNKAASL
     YPQMDDAELI DMLTRAIFVA DIWGRLDAAA DH