ID   DPO3B_BUCBP             Reviewed;         371 AA.
AC   Q89B36;
DT   30-MAY-2003, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2003, sequence version 1.
DT   03-AUG-2022, entry version 103.
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=bbp_011;
OS   Buchnera aphidicola subsp. Baizongia pistaciae (strain Bp).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=224915;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Bp;
RX   PubMed=12522265; DOI=10.1073/pnas.0235981100;
RA   van Ham R.C.H.J., Kamerbeek J., Palacios C., Rausell C., Abascal F.,
RA   Bastolla U., Fernandez J.M., Jimenez L., Postigo M., Silva F.J.,
RA   Tamames J., Viguera E., Latorre A., Valencia A., Moran F., Moya A.;
RT   "Reductive genome evolution in Buchnera aphidicola.";
RL   Proc. Natl. Acad. Sci. U.S.A. 100:581-586(2003).
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; AE016826; AAO26755.1; -; Genomic_DNA.
DR   RefSeq; WP_011091156.1; NC_004545.1.
DR   AlphaFoldDB; Q89B36; -.
DR   SMR; Q89B36; -.
DR   STRING; 224915.bbp_011; -.
DR   EnsemblBacteria; AAO26755; AAO26755; bbp_011.
DR   GeneID; 56470555; -.
DR   KEGG; bab:bbp_011; -.
DR   eggNOG; COG0592; Bacteria.
DR   HOGENOM; CLU_038149_4_2_6; -.
DR   OMA; YLIMPVR; -.
DR   OrthoDB; 1040142at2; -.
DR   Proteomes; UP000000601; 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..371
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105428"
SQ   SEQUENCE   371 AA;  42720 MW;  B7AAAECB6518B3AD CRC64;
     MKFEILNKFL IKSLKKVNNL ITRNHIFPIL ENILLIAKDN TITLTSTNID MEIKIIILDV
     TLLEPGSITV SGKKILNICQ NLPKDHNLKI QYINNKLKIV SHNNQYLLAT LPIKNFPNLK
     ISENQNNFVI SQNDLKDVLC ATYFSMAIQD LRNFLNGLFF EVRNQHLYAV ATDGYRIAIC
     KKPLHNLDKK KYNSIILPRK GVLELIKLLN YSNEVISINI SNNYFQIEFK NLIFTSKIIT
     EKFPDYTSLI LTHISKKMIL NTTLFKEALS RVAILSNENF RGVNIKNDQN KLLITTSNQH
     DEEASEIIDI IYTNIKIKMS INASYMIDIL NAIQDQEICL SKNDVTHSIQ IQAHHYKIAP
     KAIYIIMPLY A