ID   DPO3B_SYNE7             Reviewed;         375 AA.
AC   P52023; Q31SD6;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   03-AUG-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=Synpcc7942_0001;
OS   Synechococcus elongatus (strain PCC 7942 / FACHB-805) (Anacystis nidulans
OS   R2).
OC   Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus.
OX   NCBI_TaxID=1140;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8654968; DOI=10.1016/0378-1119(96)00160-6;
RA   Liu Y., Tsinoremas N.F.;
RT   "An unusual gene arrangement for the putative chromosome replication origin
RT   and circadian expression of dnaN in Synechococcus sp. strain PCC 7942.";
RL   Gene 172:105-109(1996).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 7942 / FACHB-805;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA   Kyrpides N., Lykidis A., Richardson P.;
RT   "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL   Submitted (AUG-2005) to the EMBL/GenBank/DDBJ databases.
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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=ABB56033.1; Type=Erroneous initiation; Note=Extended N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; U33322; AAA75109.1; -; Genomic_DNA.
DR   EMBL; CP000100; ABB56033.1; ALT_INIT; Genomic_DNA.
DR   RefSeq; WP_070105208.1; NZ_JACJTX010000002.1.
DR   AlphaFoldDB; P52023; -.
DR   SMR; P52023; -.
DR   STRING; 1140.Synpcc7942_0001; -.
DR   PRIDE; P52023; -.
DR   EnsemblBacteria; ABB56033; ABB56033; Synpcc7942_0001.
DR   KEGG; syf:Synpcc7942_0001; -.
DR   eggNOG; COG0592; Bacteria.
DR   HOGENOM; CLU_038149_4_1_3; -.
DR   BioCyc; SYNEL:SYNPCC7942_0001-MON; -.
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..375
FT                   /note="Beta sliding clamp"
FT                   /id="PRO_0000105474"
SQ   SEQUENCE   375 AA;  40466 MW;  74505527612BC9E7 CRC64;
     MKLVCRQNEL NTSLSLVSRA VPSRPNHPVL ANVLLAADAG TQRLSLTAFD LSLGIQTSFA
     AQVERSGAIT LPAKLLNDIV SRLPNDSDVT LEDNDAAATL SVGSGQYQMR GISADEFPEL
     PLVQSQEALQ LSASALIEGL RGTLFATSGD ETKQILTGVH LKVQPDGLEF AATDGHRLAV
     VKTENAAATP ATEFAVTVPS RALRDLERMI AIRGSDEAIA LYHDQGQTVF QWGDQYLTSR
     TLDGQYPNYG QLIPREFNRN VAVDRKRLLA ALERIAVLAD QQNNAIRLSL DPENNRLALA
     VDAQDVGSGQ EAVPAEIIGE PLEIAFNVRY LAEGLKALNT TDIQIQLNSN TSPVVLSPLG
     PVKITYLVMP IQLRS