ID   DPO3B_HELPJ             Reviewed;         374 AA.
AC   Q9ZLX4;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1999, sequence version 1.
DT   25-MAY-2022, entry version 113.
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=jhp_0452;
OS   Helicobacter pylori (strain J99 / ATCC 700824) (Campylobacter pylori J99).
OC   Bacteria; Proteobacteria; Epsilonproteobacteria; Campylobacterales;
OC   Helicobacteraceae; Helicobacter.
OX   NCBI_TaxID=85963;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=J99 / ATCC 700824;
RX   PubMed=9923682; DOI=10.1038/16495;
RA   Alm R.A., Ling L.-S.L., Moir D.T., King B.L., Brown E.D., Doig P.C.,
RA   Smith D.R., Noonan B., Guild B.C., deJonge B.L., Carmel G., Tummino P.J.,
RA   Caruso A., Uria-Nickelsen M., Mills D.M., Ives C., Gibson R., Merberg D.,
RA   Mills S.D., Jiang Q., Taylor D.E., Vovis G.F., Trust T.J.;
RT   "Genomic sequence comparison of two unrelated isolates of the human gastric
RT   pathogen Helicobacter pylori.";
RL   Nature 397:176-180(1999).
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; AE001439; AAD06030.1; -; Genomic_DNA.
DR   PIR; A71931; A71931.
DR   RefSeq; WP_000704288.1; NC_000921.1.
DR   AlphaFoldDB; Q9ZLX4; -.
DR   SMR; Q9ZLX4; -.
DR   STRING; 85963.jhp_0452; -.
DR   EnsemblBacteria; AAD06030; AAD06030; jhp_0452.
DR   KEGG; hpj:jhp_0452; -.
DR   eggNOG; COG0592; Bacteria.
DR   OMA; YLIMPVR; -.
DR   Proteomes; UP000000804; 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   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; Transferase.
FT   CHAIN           1..374
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105439"
SQ   SEQUENCE   374 AA;  42047 MW;  B0D55FE670AD55D5 CRC64;
     MKISVSKNDL ENTLRYLQAF LDKKDASSIA SHIHLEVIKE KLFLKASDSD IGLKSYISTQ
     STDKEGVGTI NGKKFLDIIS CLKDSNIVLE TKDDSLVIKQ NKSSFKLPMF DADEFPEFPV
     IDPKVSLEIN APFLVDAFKK IAPVIEQTSH KRELAGVLMQ FNQKHQTLSV VGTDTKRLSY
     TQLEKISIHS TEEDISCILP KRALLEILKL FYENFSFKSD GMLAVVENET HAFFTKLIDG
     NYPDYQKILP KEYTSSFTLG KEEFKEGIKL CSSLSSTIKL TLEKNNALFE SLDSEHSETA
     KTSVEIEKGL DIEKAFHLGV NAKFFLEALN ALGTTQFVLK CNEPSSPFLI QEPLDEKQSH
     LNAKISTLMM PITL