ID   CAS2_STRTR              Reviewed;         114 AA.
AC   G3ECR3;
DT   13-JUN-2012, integrated into UniProtKB/Swiss-Prot.
DT   16-NOV-2011, sequence version 1.
DT   03-AUG-2022, entry version 34.
DE   RecName: Full=CRISPR-associated endoribonuclease Cas2;
DE            EC=3.1.-.-;
GN   Name=cas2;
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). Functions as a ssRNA-specific endoribonuclease. Involved in
CC       the integration of spacer DNA into the CRISPR cassette (By similarity).
CC       {ECO:0000250, ECO:0000305}.
CC   -!- FUNCTION: When the CRISPR3/cas system consisting of cas9-cas1-cas2-
CC       csn2-CRISPR3 or just cas9-CRISPR3 is expressed in E.coli it prevents
CC       plasmids homologous to spacers 1 or 2 from transforming.
CC       {ECO:0000269|PubMed:21813460}.
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000250};
CC   -!- SUBUNIT: Homodimer, forms a heterotetramer with a Cas1 homodimer.
CC       {ECO:0000250}.
CC   -!- DISRUPTION PHENOTYPE: Plasmid transformation is still inhibited.
CC       {ECO:0000269|PubMed:21813460}.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated endoribonuclease Cas2
CC       protein family. {ECO:0000305}.
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DR   EMBL; HQ712120; AEM62889.1; -; Genomic_DNA.
DR   RefSeq; WP_023909843.1; NZ_WMLD01000001.1.
DR   PDB; 6QXF; EM; 3.60 A; K/N/Q/T=1-114.
DR   PDB; 6QXT; EM; 8.90 A; K/N/Q/T/W/X/k/n/q/t/w/x=1-114.
DR   PDB; 6QY3; EM; 9.10 A; K/N/Q/T/W/X/k/n/q/t/w/x=1-114.
DR   PDBsum; 6QXF; -.
DR   PDBsum; 6QXT; -.
DR   PDBsum; 6QY3; -.
DR   AlphaFoldDB; G3ECR3; -.
DR   SMR; G3ECR3; -.
DR   STRING; 322159.STER_1475; -.
DR   eggNOG; COG3512; Bacteria.
DR   GO; GO:0004521; F:endoribonuclease 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   HAMAP; MF_01471; Cas2; 1.
DR   InterPro; IPR021127; CRISPR_associated_Cas2.
DR   InterPro; IPR019199; Virulence_VapD/CRISPR_Cas2.
DR   Pfam; PF09827; CRISPR_Cas2; 1.
DR   TIGRFAMs; TIGR01573; cas2; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Antiviral defense; Endonuclease; Hydrolase; Magnesium;
KW   Metal-binding; Nuclease.
FT   CHAIN           1..114
FT                   /note="CRISPR-associated endoribonuclease Cas2"
FT                   /id="PRO_0000417731"
FT   BINDING         13
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   114 AA;  13413 MW;  B4B7677D88CEA6D6 CRC64;
     MSYRYMRMIL MFDMPTDTAE ERKAYRKFRK FLLSEGFIMH QFSVYSKLLL NHTANTAMVG
     RLKANNPKKG NITILTVTEK QFARMIYLYG DKNTSIANSE ERLVFLGDNY CDED