ID   CAS1_STRTR              Reviewed;         289 AA.
AC   G3ECR2;
DT   13-JUN-2012, integrated into UniProtKB/Swiss-Prot.
DT   16-NOV-2011, sequence version 1.
DT   03-AUG-2022, entry version 40.
DE   RecName: Full=CRISPR-associated endonuclease Cas1;
DE            EC=3.1.-.-;
GN   Name=cas1;
OS   Streptococcus thermophilus.
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae;
OC   Streptococcus.
OX   NCBI_TaxID=1308;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION IN PLASMID RESISTANCE,
RP   EXPRESSION OF CRISPR3/CAS IN E.COLI, AND DISRUPTION PHENOTYPE.
RC   STRAIN=DGCC7710;
RX   PubMed=21813460; DOI=10.1093/nar/gkr606;
RA   Sapranauskas R., Gasiunas G., Fremaux C., Barrangou R., Horvath P.,
RA   Siksnys V.;
RT   "The Streptococcus thermophilus CRISPR/Cas system provides immunity in
RT   Escherichia coli.";
RL   Nucleic Acids Res. 39:9275-9282(2011).
CC   -!- FUNCTION: CRISPR (clustered regularly interspaced short palindromic
CC       repeat), is an adaptive immune system that provides protection against
CC       mobile genetic elements (viruses, transposable elements and conjugative
CC       plasmids). CRISPR clusters contain spacers, sequences complementary to
CC       antecedent mobile elements, and target invading nucleic acids. CRISPR
CC       clusters are transcribed and processed into CRISPR RNA (crRNA)
CC       (Probable). Acts as a dsDNA endonuclease. Involved in the integration
CC       of spacer DNA into the CRISPR cassette (By similarity). When the
CC       CRISPR3/cas system consisting of cas9-cas1-cas2-csn2-CRISPR3 or just
CC       cas9-CRISPR3 is expressed in E.coli it prevents plasmids homologous to
CC       spacers 1 or 2 from transforming. {ECO:0000250,
CC       ECO:0000269|PubMed:21813460, ECO:0000305}.
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000250};
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000250};
CC   -!- SUBUNIT: Homodimer, forms a heterotetramer with a Cas2 homodimer.
CC       {ECO:0000250}.
CC   -!- DISRUPTION PHENOTYPE: Plasmid transformation is still inhibited.
CC       {ECO:0000269|PubMed:21813460}.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated endonuclease Cas1 family.
CC       {ECO:0000305}.
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DR   EMBL; HQ712120; AEM62888.1; -; Genomic_DNA.
DR   RefSeq; WP_011681469.1; NZ_WMLD01000001.1.
DR   PDB; 6QXF; EM; 3.60 A; I/J/L/M/O/P/R/S=1-289.
DR   PDB; 6QXT; EM; 8.90 A; I/J/L/M/O/P/R/S/U/V/Y/Z/i/j/l/m/o/p/r/s/u/v/y/z=1-289.
DR   PDB; 6QY3; EM; 9.10 A; I/J/L/M/O/P/R/S/U/V/Y/Z/i/j/l/m/o/p/r/s/u/v/y/z=1-289.
DR   PDBsum; 6QXF; -.
DR   PDBsum; 6QXT; -.
DR   PDBsum; 6QY3; -.
DR   AlphaFoldDB; G3ECR2; -.
DR   SMR; G3ECR2; -.
DR   STRING; 322159.STER_1476; -.
DR   PRIDE; G3ECR2; -.
DR   eggNOG; COG1518; Bacteria.
DR   OMA; DDLMEPY; -.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0004520; F:endodeoxyribonuclease activity; IEA:InterPro.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0051607; P:defense response to virus; IEA:UniProtKB-UniRule.
DR   GO; GO:0043571; P:maintenance of CRISPR repeat elements; IEA:UniProtKB-UniRule.
DR   Gene3D; 1.20.120.920; -; 1.
DR   HAMAP; MF_01470; Cas1; 1.
DR   InterPro; IPR002729; CRISPR-assoc_Cas1.
DR   InterPro; IPR042206; CRISPR-assoc_Cas1_C.
DR   InterPro; IPR019855; CRISPR-assoc_Cas1_NMENI.
DR   Pfam; PF01867; Cas_Cas1; 1.
DR   TIGRFAMs; TIGR00287; cas1; 1.
DR   TIGRFAMs; TIGR03639; cas1_NMENI; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Antiviral defense; DNA-binding; Endonuclease; Hydrolase;
KW   Magnesium; Manganese; Metal-binding; Nuclease.
FT   CHAIN           1..289
FT                   /note="CRISPR-associated endonuclease Cas1"
FT                   /id="PRO_0000417963"
FT   BINDING         149
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /evidence="ECO:0000250"
FT   BINDING         205
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /evidence="ECO:0000250"
FT   BINDING         220
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   289 AA;  33824 MW;  344B547C6276BE51 CRC64;
     MAGWRTVVVN IHSKLSYKNN HLIFRNSYKT EMIHLSEIDI LLLETTDIVL TTMLVKRLVD
     ENILVIFCDD KRLPTAFLTP YYARHDSSLQ IARQIAWKEN VKCEVWTAII AQKILNQSYY
     LGECSFFEKS QSIMELYHGL ERFDPSNREG HSARIYFNTL FGNDFTRESD NDINAALDYG
     YTLLLSMFAR EVVVCGCMTQ IGLKHANQFN QFNLASDIME PFRPIIDRIV YQNRHNNFVK
     IKKELFSIFS ETYLYNGKEM YLSNIVSDYT KKVIKALNQL GEEIPEFRI