ID   NP_BPB03                Reviewed;         100 AA.
AC   Q37886;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   29-SEP-2021, entry version 62.
DE   RecName: Full=Histone-like protein p6 {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Double-stranded DNA-binding protein {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Double-stranded DNA-binding protein p6 {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Gene product 6 {ECO:0000250|UniProtKB:P03685};
DE            Short=gp6 {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Histone-like binding protein {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Nucleoid-associated protein p6 {ECO:0000250|UniProtKB:P03685};
DE   AltName: Full=Protein p6 {ECO:0000250|UniProtKB:P03685};
GN   Name=6;
OS   Bacillus phage B103 (Bacteriophage B103).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Salasmaviridae; Picovirinae; Beecentumtrevirus.
OX   NCBI_TaxID=10778;
OH   NCBI_TaxID=1423; Bacillus subtilis.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=9358052; DOI=10.1016/s0378-1119(97)00363-6;
RA   Pecenkova T., Benes V., Paces J., Vlcek C., Paces V.;
RT   "Bacteriophage B103: complete DNA sequence of its genome and relationship
RT   to other Bacillus phages.";
RL   Gene 199:157-163(1997).
CC   -!- FUNCTION: Histone-like nucleoprotein that binds to the viral dsDNA and
CC       responsible for wrapping and compacting the viral DNA about 4-fold.
CC       Forms a nucleoprotein complex in which the DNA adopts a right-handed
CC       toroidal conformation winding around a protein core. Binds ito most, if
CC       not all, the viral genome, although with different affinity, the
CC       highest one corresponding to the genome ends. The formation of the
CC       nucleoprotein complex at the genome ends, activates the initiation of
CC       viral DNA replication. The binding of p6 would recruit the complex
CC       formed by the TP and the DNA polymerase to the origin. Protein p6 also
CC       represses early transcription from promoter C2, and, together with
CC       protein p4, represses transcription from promoters A2b and A2c and
CC       activates late transcription from promoter A3. Protein p6 is therefore
CC       involved in the early to late transcription switch. The formation of
CC       the nucleoprotein complex at the right end of the phage genome where
CC       the early promoter C2 is located affects local topology, which may
CC       contribute to the promoter repression. {ECO:0000250|UniProtKB:P03685}.
CC   -!- SUBUNIT: Homodimer. Homomultimer. Binds to double-stranded DNA giving
CC       rise to multimeric nucleoprotein complexes. Binding specificity for the
CC       viral DNA is based on supercoiling, the viral genome having a negative
CC       superhelicity lower than that of plasmid DNA. Interacts with the DNA
CC       replication protein p17; this interaction optimizes the binding of
CC       protein p6 at the viral DNA ends, thus favoring the initiation of
CC       replication. {ECO:0000250|UniProtKB:P03685}.
CC   -!- DOMAIN: The N-terminus is involved in DNA-binding.
CC       {ECO:0000250|UniProtKB:P03685}.
CC   -!- SIMILARITY: Belongs to the phi29likevirus histone-like protein p6
CC       family. {ECO:0000305}.
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DR   EMBL; X99260; CAA67653.1; -; Genomic_DNA.
DR   RefSeq; NP_690639.1; NC_004165.1.
DR   GeneID; 955359; -.
DR   KEGG; vg:955359; -.
DR   Proteomes; UP000000971; Genome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0030261; P:chromosome condensation; IEA:UniProtKB-KW.
DR   GO; GO:0006260; P:DNA replication; IEA:UniProtKB-KW.
DR   GO; GO:0039693; P:viral DNA genome replication; IEA:UniProtKB-KW.
DR   InterPro; IPR035188; Histone-like_p6.
DR   Pfam; PF17548; p6; 1.
PE   3: Inferred from homology;
KW   DNA condensation; DNA replication; DNA-binding; Early protein; Repressor;
KW   Transcription; Transcription regulation; Viral DNA replication.
FT   CHAIN           1..100
FT                   /note="Histone-like protein p6"
FT                   /id="PRO_0000106567"
FT   DNA_BIND        1..19
FT                   /evidence="ECO:0000250|UniProtKB:P03685"
SQ   SEQUENCE   100 AA;  11367 MW;  DFA32866644580E8 CRC64;
     MRKMMQREVT YTTAQLARMK MEDGQVTAEV LEPVTLIGNL SVEQAQREIN KRPEFKENPA
     QVVGVEPNTQ LYELPLDVFL EHATVKERPA AKEEVAEVQA