ID   CSN2_STRTR              Reviewed;         219 AA.
AC   G3ECR4;
DT   13-JUN-2012, integrated into UniProtKB/Swiss-Prot.
DT   16-NOV-2011, sequence version 1.
DT   03-AUG-2022, entry version 25.
DE   RecName: Full=CRISPR-associated protein Csn2;
GN   Name=csn2;
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). Binds dsDNA (By similarity). When the CRISPR3/cas system
CC       consisting of cas9-cas1-cas2-csn2-CRISPR3 or just cas9-CRISPR3 is
CC       expressed in E.coli it prevents plasmids homologous to spacers 1 or 2
CC       from transforming. {ECO:0000250, ECO:0000269|PubMed:21813460,
CC       ECO:0000305}.
CC   -!- COFACTOR:
CC       Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000250};
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250}.
CC   -!- DISRUPTION PHENOTYPE: Plasmid transformation is still inhibited.
CC       {ECO:0000269|PubMed:21813460}.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated Csn2 protein family.
CC       {ECO:0000305}.
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DR   EMBL; HQ712120; AEM62890.1; -; Genomic_DNA.
DR   RefSeq; WP_014608593.1; NZ_WMLD01000001.1.
DR   PDB; 6QXF; EM; 3.60 A; A/B/C/D/E/F/G/H=1-219.
DR   PDB; 6QXT; EM; 8.90 A; A/B/C/D/E/F/G/H/a/b/c/d/e/f/g/h=1-219.
DR   PDB; 6QY3; EM; 9.10 A; A/B/C/D/E/F/G/H/a/b/c/d/e/f/g/h=1-219.
DR   PDBsum; 6QXF; -.
DR   PDBsum; 6QXT; -.
DR   PDBsum; 6QY3; -.
DR   AlphaFoldDB; G3ECR4; -.
DR   SMR; G3ECR4; -.
DR   STRING; 322159.STER_1474; -.
DR   eggNOG; ENOG502ZVZK; Bacteria.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0051607; P:defense response to virus; IEA:UniProtKB-KW.
DR   Gene3D; 3.40.50.11940; -; 2.
DR   InterPro; IPR010146; CRISPR-assoc_prot_Csn2-typ.
DR   InterPro; IPR038600; Csn2_sf.
DR   Pfam; PF09711; Cas_Csn2; 1.
DR   TIGRFAMs; TIGR01866; cas_Csn2; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Antiviral defense; Calcium; DNA-binding; Metal-binding.
FT   CHAIN           1..219
FT                   /note="CRISPR-associated protein Csn2"
FT                   /id="PRO_0000417880"
FT   BINDING         138
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
FT   BINDING         150
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   219 AA;  25513 MW;  6724B909085E7349 CRC64;
     MKINFSLLDE PMEVNLGTVL VIEDVSVFAQ LVKEFYQYDE QSNLTIFDSK IRSIRSSELL
     LITDILGYDI NTSQVLKLLH TDIVSQLNDK PEVRSEIDSL VSLITDIIMA ECIENELDIE
     YDEITLLELI KALGVRIETK SCTVFEKIFE ILQIFKYLVK KRILVFVNSL SYFSKDEIYQ
     ILEYTKLSQA DVLFLEPRQI EGIQQFILDK DYILMPYNN