ID   DPO3B_LACLA             Reviewed;         380 AA.
AC   Q9CJJ1;
DT   26-SEP-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2001, sequence version 1.
DT   25-MAY-2022, entry version 106.
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=LL0002; ORFNames=L0275;
OS   Lactococcus lactis subsp. lactis (strain IL1403) (Streptococcus lactis).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Lactococcus.
OX   NCBI_TaxID=272623;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=IL1403;
RX   PubMed=11337471; DOI=10.1101/gr.gr-1697r;
RA   Bolotin A., Wincker P., Mauger S., Jaillon O., Malarme K., Weissenbach J.,
RA   Ehrlich S.D., Sorokin A.;
RT   "The complete genome sequence of the lactic acid bacterium Lactococcus
RT   lactis ssp. lactis IL1403.";
RL   Genome Res. 11:731-753(2001).
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; AE005176; AAK04100.1; -; Genomic_DNA.
DR   PIR; B86625; B86625.
DR   RefSeq; NP_266158.1; NC_002662.1.
DR   RefSeq; WP_003130856.1; NC_002662.1.
DR   AlphaFoldDB; Q9CJJ1; -.
DR   SMR; Q9CJJ1; -.
DR   STRING; 272623.L0275; -.
DR   PaxDb; Q9CJJ1; -.
DR   EnsemblBacteria; AAK04100; AAK04100; L0275.
DR   GeneID; 60356870; -.
DR   GeneID; 66440993; -.
DR   KEGG; lla:L0275; -.
DR   PATRIC; fig|272623.7.peg.2; -.
DR   eggNOG; COG0592; Bacteria.
DR   HOGENOM; CLU_038149_2_0_9; -.
DR   OMA; YLIMPVR; -.
DR   Proteomes; UP000002196; 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..380
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105440"
SQ   SEQUENCE   380 AA;  42264 MW;  2D54BD83932029B0 CRC64;
     MIKFSINKNA FQNALRITKQ AIGSKVTIPA LTKLKIEVEE NGITLIGSNG QISIKNFLPV
     DNKDASMLIS GTGSVLLEAA FFENVVSQLP EVTLEFTEKE QKQVLLTSGK SEITLKGLDS
     EIYPHLQEIS EGSSLKMKVK VLKEIFTETV FAVSTQENRP IFTGVHLETL STGELKAVAT
     DSHRMSQRLL PLEDSELKFD VILPSKSINS FKNVFTNDEE EIEIFISGSQ MLFRNETISY
     YSRLIEGSYP DTNRLIPNEA DYTLDLVFDA AQLRHTMDRA RLLTVMTTNG TVKLTVSGDS
     VVTTANSPEV GSVHEELTAL SKEGNDLAIS FNPEYLIDAL KVIKAPEVRI RFISNVRPFT
     LQPRNEESGF VQLITPVRTN