ID   DPO3B_CHLTR             Reviewed;         416 AA.
AC   O84078;
DT   01-JUN-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1998, sequence version 1.
DT   25-MAY-2022, entry version 107.
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=CT_075;
OS   Chlamydia trachomatis (strain D/UW-3/Cx).
OC   Bacteria; Chlamydiae; Chlamydiales; Chlamydiaceae;
OC   Chlamydia/Chlamydophila group; Chlamydia.
OX   NCBI_TaxID=272561;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=D/UW-3/Cx;
RX   PubMed=9784136; DOI=10.1126/science.282.5389.754;
RA   Stephens R.S., Kalman S., Lammel C.J., Fan J., Marathe R., Aravind L.,
RA   Mitchell W.P., Olinger L., Tatusov R.L., Zhao Q., Koonin E.V., Davis R.W.;
RT   "Genome sequence of an obligate intracellular pathogen of humans: Chlamydia
RT   trachomatis.";
RL   Science 282:754-759(1998).
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; AE001273; AAC67666.1; -; Genomic_DNA.
DR   PIR; E71559; E71559.
DR   RefSeq; NP_219578.1; NC_000117.1.
DR   RefSeq; WP_010725022.1; NC_000117.1.
DR   AlphaFoldDB; O84078; -.
DR   SMR; O84078; -.
DR   STRING; 813.O172_00415; -.
DR   EnsemblBacteria; AAC67666; AAC67666; CT_075.
DR   GeneID; 884117; -.
DR   KEGG; ctr:CT_075; -.
DR   PATRIC; fig|272561.5.peg.84; -.
DR   HOGENOM; CLU_038149_4_0_0; -.
DR   InParanoid; O84078; -.
DR   OMA; YLIMPVR; -.
DR   Proteomes; UP000000431; 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:0006271; P:DNA strand elongation involved in DNA replication; IBA:GO_Central.
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..416
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105433"
SQ   SEQUENCE   416 AA;  46529 MW;  F328D087A8930683 CRC64;
     MNFRLHGAFS NPSFVKIFFT KASPERRLTC FHVTKHGYSF QTDLHDYRKI MKFVISRNEL
     GNLIKKVQNV VPQSTPIPVL THVLIESCND ELVFTATDLT VSTRCVVKAK VYESGSVTIP
     SRRFFQLIRE LTEANIEVAA HSGEMATITS GSSCFRLLSM GKEDFPMLPD MQNALRFTLD
     SERLKDMFQR TSFAVSREES RYVLTGVLLS IANGTMTVVG TDGKRLAKID TEISLDPSFS
     GDYIIPIKAV EEIIRMSSED VQSTIFLDQT KIAVECGNTL LVTKLLSGEF PDFSPVISTH
     SSVQLDLHRE ELISLLKQVA LFTNESSHSV KFSFSPGELT LTANCTKVGE GKVSMAVNYT
     GETLEIAFNP FFFLDILKHS RDELVQLGIS DSYNPGIITD STRSLFVIMP MRLHDD