ID   CSX1_METJA              Reviewed;         465 AA.
AC   Q59060;
DT   02-FEB-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   25-MAY-2022, entry version 89.
DE   RecName: Full=CRISPR system endoribonuclease Csx1;
DE            EC=3.1.-.-;
GN   Name=csx1; OrderedLocusNames=MJ1666;
OS   Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM
OS   10045 / NBRC 100440) (Methanococcus jannaschii).
OC   Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales;
OC   Methanocaldococcaceae; Methanocaldococcus.
OX   NCBI_TaxID=243232;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440;
RX   PubMed=8688087; DOI=10.1126/science.273.5278.1058;
RA   Bult C.J., White O., Olsen G.J., Zhou L., Fleischmann R.D., Sutton G.G.,
RA   Blake J.A., FitzGerald L.M., Clayton R.A., Gocayne J.D., Kerlavage A.R.,
RA   Dougherty B.A., Tomb J.-F., Adams M.D., Reich C.I., Overbeek R.,
RA   Kirkness E.F., Weinstock K.G., Merrick J.M., Glodek A., Scott J.L.,
RA   Geoghagen N.S.M., Weidman J.F., Fuhrmann J.L., Nguyen D., Utterback T.R.,
RA   Kelley J.M., Peterson J.D., Sadow P.W., Hanna M.C., Cotton M.D.,
RA   Roberts K.M., Hurst M.A., Kaine B.P., Borodovsky M., Klenk H.-P.,
RA   Fraser C.M., Smith H.O., Woese C.R., Venter J.C.;
RT   "Complete genome sequence of the methanogenic archaeon, Methanococcus
RT   jannaschii.";
RL   Science 273:1058-1073(1996).
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). The
CC       type III Csm effector complex binds crRNA and acts as a crRNA-guided
CC       RNase, DNase and cyclic oligoadenylate synthase; binding of target RNA
CC       cognate to the crRNA is required for all activities.
CC       {ECO:0000250|UniProtKB:Q97YD5}.
CC   -!- FUNCTION: Activated by cyclic oligoadenylate (cOA) to
CC       endonucleolytically degrade linear RNA; when cOA levels decrease the
CC       RNase activity of Csx1 is abrogated. {ECO:0000250|UniProtKB:Q97YD5}.
CC   -!- ACTIVITY REGULATION: The RNase activity is stimulated by cOA.
CC       {ECO:0000250|UniProtKB:Q97YD5}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000250|UniProtKB:Q97YD5}.
CC   -!- MISCELLANEOUS: Encoded in a type III-A CRISPR locus. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated Csx1 family.
CC       {ECO:0000305}.
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DR   EMBL; L77117; AAB99691.1; -; Genomic_DNA.
DR   PIR; H64507; H64507.
DR   RefSeq; WP_010871190.1; NC_000909.1.
DR   AlphaFoldDB; Q59060; -.
DR   SMR; Q59060; -.
DR   STRING; 243232.MJ_1666; -.
DR   PRIDE; Q59060; -.
DR   EnsemblBacteria; AAB99691; AAB99691; MJ_1666.
DR   GeneID; 1452575; -.
DR   KEGG; mja:MJ_1666; -.
DR   eggNOG; arCOG03433; Archaea.
DR   HOGENOM; CLU_044033_0_0_2; -.
DR   InParanoid; Q59060; -.
DR   OMA; ILIAPWG; -.
DR   OrthoDB; 110543at2157; -.
DR   PhylomeDB; Q59060; -.
DR   Proteomes; UP000000805; Chromosome.
DR   GO; GO:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR   GO; GO:0051607; P:defense response to virus; IEA:UniProtKB-KW.
DR   InterPro; IPR013383; CRISPR-assoc_prot_DxTHG_CS.
DR   InterPro; IPR010171; CRISPR_Csx1.
DR   InterPro; IPR019016; Csx1-like.
DR   Pfam; PF09455; Cas_DxTHG; 1.
DR   TIGRFAMs; TIGR01897; cas_MJ1666; 1.
DR   TIGRFAMs; TIGR02549; CRISPR_DxTHG; 1.
PE   3: Inferred from homology;
KW   Antiviral defense; Endonuclease; Hydrolase; Nuclease; Reference proteome.
FT   CHAIN           1..465
FT                   /note="CRISPR system endoribonuclease Csx1"
FT                   /id="PRO_0000107463"
SQ   SEQUENCE   465 AA;  54500 MW;  ACB9E442EEF94173 CRC64;
     MQKILIAPWG NFSSWKKVIY SFNGVEKESK SSLSAIYDKI NPDKVYILVL DTLSNLESEN
     YGDIVKEVKE KTENFIKENL NIDNYEVIVC PGVGTFYNKD FEKYFKFYGN LTDYYSFALY
     ELSKRLDGDL EVHLDLTHGL NYMPVLTYRV IKDLLEILAI KNKVRLVVYN SDPYVGREKE
     ILNIHTVEDV IIKPSYDIKG MTLDFLDATK FVDKKEIGKI KKEINMNPKI KELRIMKQNI
     NAFIASIVYA LPLVYSTFFV KKDKIEIYLN ELIGAFISNI KINPEDKILK RYLYFGEGFN
     SLVKAYFASK ISEIPQLIKD ELSLEEIDEL KNTLFKENPN SQYIKNEISS LYNIINTKYK
     EEELSEILGN WTPIYKIRRE NIDKFKIRNF LAHAGFEKSV TEIYISVENK NGKIELSEKT
     SLRYNKNYIE EKNGIKRFIF KYKDKNGKVE EINILEKIEE ILLNK