ID   SCAFB_BPPHK             Reviewed;         117 AA.
AC   Q38036;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1997, sequence version 1.
DT   03-AUG-2022, entry version 70.
DE   RecName: Full=Internal scaffolding protein B;
DE            EC=3.4.-.- {ECO:0000250|UniProtKB:P03633};
DE   AltName: Full=Scaffolding protein B;
DE            Short=GPB;
GN   Name=B;
OS   Enterobacteria phage phiK (Bacteriophage phi-K).
OC   Viruses; Monodnaviria; Sangervirae; Phixviricota; Malgrandaviricetes;
OC   Petitvirales; Microviridae; Bullavirinae; Alphatrevirus.
OX   NCBI_TaxID=10848;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] (PHI-K AND MUTANT PHI KHT).
RX   PubMed=8827438; DOI=10.1093/oxfordjournals.jbchem.a021348;
RA   Kodaira K., Oki M., Kakikawa M., Kimoto H., Taketo A.;
RT   "The virion proteins encoded by bacteriophage phi K and its host-range
RT   mutant phi KhT: host-range determination and DNA binding properties.";
RL   J. Biochem. 119:1062-1069(1996).
CC   -!- FUNCTION: Participates in the assembly of the viral procapsid in the
CC       cytoplasm. Forms first a 12S pre-assembly complex with protein H, and F
CC       and G pentamers, then twelve 12S complexes are joined by the D protein
CC       to form the procapsid. Internal scaffold protein B is released from the
CC       procapsid upon genome packaging. Autoproteolytic activity cleaves
CC       protein B and probably facilitates its removal through the pores of the
CC       procapsid. {ECO:0000250|UniProtKB:P03633}.
CC   -!- SUBUNIT: Component of the procapsid complex composed of 60 copies of
CC       the internally located B, 240 copies of the external scaffolding
CC       protein D, 60 copies of each of the viral structural proteins F and G
CC       proteins, and 12 copies of H. {ECO:0000250|UniProtKB:P03633}.
CC   -!- SUBCELLULAR LOCATION: Host cytoplasm {ECO:0000250|UniProtKB:P03633}.
CC   -!- PTM: The proteolytic cleavage of the internal scaffolding protein B
CC       releases the scaffold protein in order to continue virion assembly.
CC       {ECO:0000250|UniProtKB:P03633}.
CC   -!- MISCELLANEOUS: Phi KhT, a host-range mutant of phi K, can grow on
CC       E.coli C and B, besides K12, and is more thermosensitive than the
CC       parental phage phi K.
CC   -!- SIMILARITY: Belongs to the microviridae B protein family.
CC       {ECO:0000305}.
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DR   EMBL; X60323; CAA42885.1; -; Genomic_DNA.
DR   RefSeq; NP_043943.1; NC_001730.1.
DR   SMR; Q38036; -.
DR   GeneID; 1261193; -.
DR   KEGG; vg:1261193; -.
DR   Proteomes; UP000002122; Genome.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0008233; F:peptidase activity; IEA:UniProtKB-KW.
DR   GO; GO:0006508; P:proteolysis; IEA:UniProtKB-KW.
DR   GO; GO:0019069; P:viral capsid assembly; IEA:InterPro.
DR   Gene3D; 4.10.1260.10; -; 1.
DR   InterPro; IPR003513; Phage_B.
DR   InterPro; IPR038149; Phage_B_sf.
DR   Pfam; PF02304; Phage_B; 1.
PE   3: Inferred from homology;
KW   Autocatalytic cleavage; Host cytoplasm; Hydrolase; Protease;
KW   Viral capsid assembly; Viral release from host cell.
FT   CHAIN           1..117
FT                   /note="Internal scaffolding protein B"
FT                   /id="PRO_0000164869"
FT   REGION          1..65
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        1..50
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        51..65
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   SITE            74..75
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000250|UniProtKB:P03633"
FT   SITE            90..91
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000250|UniProtKB:P03633"
FT   SITE            105..106
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000250|UniProtKB:P03633"
SQ   SEQUENCE   117 AA;  13226 MW;  ABB8292704E13C0E CRC64;
     MQESINGNLS EERISGAQQP EAWNGAPVNG SPEQQSASGA ESNQLRFQSS LSDSERERQK
     ATDLEHRRAA FARHFGCAPG SEKHVESYSS FDEKDTRVQL AEFYRFNDGH LKKWGYF