ID   DPO3B_LACLM             Reviewed;         380 AA.
AC   O54376; A2RH75;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1998, sequence version 1.
DT   03-AUG-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;
DE            EC=2.7.7.7;
GN   Name=dnaN; OrderedLocusNames=llmg_0002;
OS   Lactococcus lactis subsp. cremoris (strain MG1363).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Lactococcus; Lactococcus cremoris subsp. cremoris.
OX   NCBI_TaxID=416870;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=9435243; DOI=10.1073/pnas.95.2.626;
RA   El-Karoui M., Ehrlich S.D., Gruss A.;
RT   "Identification of the lactococcal exonuclease/recombinase and its
RT   modulation by the putative Chi sequence.";
RL   Proc. Natl. Acad. Sci. U.S.A. 95:626-631(1998).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=MG1363;
RX   PubMed=17307855; DOI=10.1128/jb.01768-06;
RA   Wegmann U., O'Connell-Motherway M., Zomer A., Buist G., Shearman C.,
RA   Canchaya C., Ventura M., Goesmann A., Gasson M.J., Kuipers O.P.,
RA   van Sinderen D., Kok J.;
RT   "The complete genome sequence of the lactic acid bacterial paradigm
RT   Lactococcus lactis subsp. cremoris MG1363.";
RL   J. Bacteriol. 189:3256-3270(2007).
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   -!- CATALYTIC ACTIVITY:
CC       Reaction=a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) =
CC         diphosphate + DNA(n+1); Xref=Rhea:RHEA:22508, Rhea:RHEA-COMP:17339,
CC         Rhea:RHEA-COMP:17340, ChEBI:CHEBI:33019, ChEBI:CHEBI:61560,
CC         ChEBI:CHEBI:173112; EC=2.7.7.7;
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; U76424; AAC12964.1; -; Genomic_DNA.
DR   EMBL; AM406671; CAL96610.1; -; Genomic_DNA.
DR   PIR; T30306; T30306.
DR   RefSeq; WP_011834121.1; NZ_WJVF01000016.1.
DR   AlphaFoldDB; O54376; -.
DR   SMR; O54376; -.
DR   STRING; 416870.llmg_0002; -.
DR   EnsemblBacteria; CAL96610; CAL96610; llmg_0002.
DR   GeneID; 61108329; -.
DR   KEGG; llm:llmg_0002; -.
DR   eggNOG; COG0592; Bacteria.
DR   HOGENOM; CLU_038149_2_0_9; -.
DR   OMA; YLIMPVR; -.
DR   PhylomeDB; O54376; -.
DR   BioCyc; LLAC416870:LLMG_RS00010-MON; -.
DR   Proteomes; UP000000364; 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; Transferase.
FT   CHAIN           1..380
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105441"
SQ   SEQUENCE   380 AA;  42209 MW;  4877297F3E822644 CRC64;
     MIKFSINKTA FQNALKITKQ AIGSKVTIPA LTKLKIEVEE KGITLIGSNG QISIKNFLPA
     DNKDASMLIS GTGSVLLEAA FFENVVSQLP EVTLEFIEKE QKQVLLTSGK SEITLKGLDS
     EIYPHLQEIS EGSSLKMKVK VLKEIFTETV FAVSTQENRP IFTGVHLETL STGELKAVAT
     DSHRMSQRLL PLEDTDLKFD VILPSKSINS FKNVFTNDEE EIEIFISGSQ MLFQNETISY
     YSRLIEGSYP DTNRLIPNEA DYTLDLVFDA AQLRHTMDRA RLLTVMTTNG TVKLTVSGDS
     VVTTANSPEV GSVHEELTAL SKEGNDLSIS FNPEYLIDAL KVIKAPEVRI RFISNVRPFT
     LQPRNEESGF VQLITPVRTN