ID   DPO3B_BUCAI             Reviewed;         366 AA.
AC   P57127; Q9EVE5;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2000, sequence version 1.
DT   25-MAY-2022, entry version 111.
DE   RecName: Full=Beta sliding clamp;
DE            Short=Beta clamp;
DE            Short=Sliding clamp;
DE   AltName: Full=Beta-clamp processivity factor;
DE   AltName: Full=DNA polymerase III beta sliding clamp subunit;
DE   AltName: Full=DNA polymerase III subunit beta;
GN   Name=dnaN; OrderedLocusNames=BU011;
OS   Buchnera aphidicola subsp. Acyrthosiphon pisum (strain APS) (Acyrthosiphon
OS   pisum symbiotic bacterium).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=107806;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=11133977; DOI=10.1128/jb.183.2.785-790.2001;
RA   Wernegreen J.J., Moran N.A.;
RT   "Vertical transmission of biosynthetic plasmids in aphid endosymbionts
RT   (Buchnera).";
RL   J. Bacteriol. 183:785-790(2001).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=APS;
RX   PubMed=10993077; DOI=10.1038/35024074;
RA   Shigenobu S., Watanabe H., Hattori M., Sakaki Y., Ishikawa H.;
RT   "Genome sequence of the endocellular bacterial symbiont of aphids Buchnera
RT   sp. APS.";
RL   Nature 407:81-86(2000).
CC   -!- FUNCTION: Confers DNA tethering and processivity to DNA polymerases and
CC       other proteins. Acts as a clamp, forming a ring around DNA (a reaction
CC       catalyzed by the clamp-loading complex) which diffuses in an ATP-
CC       independent manner freely and bidirectionally along dsDNA. Initially
CC       characterized for its ability to contact the catalytic subunit of DNA
CC       polymerase III (Pol III), a complex, multichain enzyme responsible for
CC       most of the replicative synthesis in bacteria; Pol III exhibits 3'-5'
CC       exonuclease proofreading activity. The beta chain is required for
CC       initiation of replication as well as for processivity of DNA
CC       replication. {ECO:0000250|UniProtKB:P0A988}.
CC   -!- SUBUNIT: Forms a ring-shaped head-to-tail homodimer around DNA which
CC       binds and tethers DNA polymerases and other proteins to the DNA. The
CC       DNA replisome complex has a single clamp-loading complex (3 tau and 1
CC       each of delta, delta', psi and chi subunits) which binds 3 Pol III
CC       cores (1 core on the leading strand and 2 on the lagging strand) each
CC       with a beta sliding clamp dimer. Additional proteins in the replisome
CC       are other copies of gamma, psi and chi, Ssb, DNA helicase and RNA
CC       primase. {ECO:0000250|UniProtKB:P0A988}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:P0A988}.
CC   -!- SIMILARITY: Belongs to the beta sliding clamp family. {ECO:0000305}.
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DR   EMBL; AF197895; AAG33955.1; -; Genomic_DNA.
DR   EMBL; BA000003; BAB12739.1; -; Genomic_DNA.
DR   RefSeq; NP_239853.1; NC_002528.1.
DR   RefSeq; WP_010895902.1; NC_002528.1.
DR   AlphaFoldDB; P57127; -.
DR   SMR; P57127; -.
DR   STRING; 107806.10038704; -.
DR   EnsemblBacteria; BAB12739; BAB12739; BAB12739.
DR   KEGG; buc:BU011; -.
DR   PATRIC; fig|107806.10.peg.24; -.
DR   eggNOG; COG0592; Bacteria.
DR   HOGENOM; CLU_038149_4_2_6; -.
DR   OMA; KIACSLI; -.
DR   Proteomes; UP000001806; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0009360; C:DNA polymerase III complex; IEA:InterPro.
DR   GO; GO:0008408; F:3'-5' exonuclease activity; IEA:InterPro.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003887; F:DNA-directed DNA polymerase activity; IEA:UniProtKB-KW.
DR   GO; GO:0006260; P:DNA replication; IEA:UniProtKB-KW.
DR   CDD; cd00140; beta_clamp; 1.
DR   InterPro; IPR001001; DNA_polIII_beta.
DR   InterPro; IPR022635; DNA_polIII_beta_C.
DR   InterPro; IPR022637; DNA_polIII_beta_cen.
DR   InterPro; IPR022634; DNA_polIII_beta_N.
DR   PANTHER; PTHR30478; PTHR30478; 1.
DR   Pfam; PF00712; DNA_pol3_beta; 1.
DR   Pfam; PF02767; DNA_pol3_beta_2; 1.
DR   Pfam; PF02768; DNA_pol3_beta_3; 1.
DR   PIRSF; PIRSF000804; DNA_pol_III_b; 1.
DR   SMART; SM00480; POL3Bc; 1.
DR   TIGRFAMs; TIGR00663; dnan; 1.
PE   3: Inferred from homology;
KW   Cytoplasm; DNA replication; DNA-binding; DNA-directed DNA polymerase;
KW   Nucleotidyltransferase; Reference proteome; Transferase.
FT   CHAIN           1..366
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105426"
FT   CONFLICT        147
FT                   /note="A -> G (in Ref. 1; AAG33955)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        152..153
FT                   /note="RY -> PI (in Ref. 1; AAG33955)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   366 AA;  41985 MW;  334F1880E8049604 CRC64;
     MKFIINNNIL IKNLQKISRL LVKNTSLPIL DNVLINIKNG MLSLTGTNLE IELVAMIQLS
     TEHISGTATI SGRKLLDICR NSLNSSNIEM QLNNNKMHII SGNSRYILTT LPYDSFPVHH
     DFHHISEFFI PSDILKKMIE KIQFSMAKQD VRYYLNGILL EKTDRSLYAV ATDGYRLGIS
     KFFLKENIIP FSIVIPRKGV IELYRLLNIP KQPIKVLVGK NNIRVHIEDL IFTTQLIEGQ
     YPDYKSVLLE NKNNFITLNS KLLKQSLLRA AILSHEKFCG VEIHIRNGQF KVLSDNQEEE
     IAEDRFNINY TGNTVKISIN VYYIIEILNS ITSENIFLFL NNANNSIQIE AENDASILYV
     VMLLKR