ID   CSX1_SACS2              Reviewed;         377 AA.
AC   Q97YD5;
DT   05-SEP-2012, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2001, sequence version 1.
DT   25-MAY-2022, entry version 95.
DE   RecName: Full=CRISPR system endoribonuclease Csx1;
DE            EC=3.1.-.- {ECO:0000269|PubMed:30232454};
GN   Name=csx1 {ECO:0000303|PubMed:30232454}; OrderedLocusNames=SSO1389;
OS   Saccharolobus solfataricus (strain ATCC 35092 / DSM 1617 / JCM 11322 / P2)
OS   (Sulfolobus solfataricus).
OC   Archaea; Crenarchaeota; Thermoprotei; Sulfolobales; Sulfolobaceae;
OC   Saccharolobus.
OX   NCBI_TaxID=273057;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 35092 / DSM 1617 / JCM 11322 / P2;
RX   PubMed=11427726; DOI=10.1073/pnas.141222098;
RA   She Q., Singh R.K., Confalonieri F., Zivanovic Y., Allard G., Awayez M.J.,
RA   Chan-Weiher C.C.-Y., Clausen I.G., Curtis B.A., De Moors A., Erauso G.,
RA   Fletcher C., Gordon P.M.K., Heikamp-de Jong I., Jeffries A.C., Kozera C.J.,
RA   Medina N., Peng X., Thi-Ngoc H.P., Redder P., Schenk M.E., Theriault C.,
RA   Tolstrup N., Charlebois R.L., Doolittle W.F., Duguet M., Gaasterland T.,
RA   Garrett R.A., Ragan M.A., Sensen C.W., Van der Oost J.;
RT   "The complete genome of the crenarchaeon Sulfolobus solfataricus P2.";
RL   Proc. Natl. Acad. Sci. U.S.A. 98:7835-7840(2001).
RN   [2]
RP   FUNCTION, ACTIVITY REGULATION, AND SUBUNIT.
RC   STRAIN=ATCC 35092 / DSM 1617 / JCM 11322 / P2;
RX   PubMed=30232454; DOI=10.1038/s41586-018-0557-5;
RA   Athukoralage J.S., Rouillon C., Graham S., Grueschow S., White M.F.;
RT   "Ring nucleases deactivate type III CRISPR ribonucleases by degrading
RT   cyclic oligoadenylate.";
RL   Nature 562:277-280(2018).
RN   [3]
RP   X-RAY CRYSTALLOGRAPHY (1.70 ANGSTROMS), AND SUBUNIT.
RC   STRAIN=ATCC 35092 / DSM 1617 / JCM 11322 / P2;
RA   Tan K., Skarina T., Onopriyenko O., Savchenko A., Edwards A.,
RA   Joachimiak A.;
RT   "The crystal structure of a conserved hypothetical protein from Sulfolobus
RT   solfataricus P2.";
RL   Submitted (AUG-2006) to the PDB data bank.
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). The type III Csm effector complex binds crRNA and acts as a
CC       crRNA-guided RNase, DNase and cyclic oligoadenylate synthase; binding
CC       of target RNA cognate to the crRNA is required for all activities.
CC       {ECO:0000305|PubMed:30232454}.
CC   -!- FUNCTION: Activated by cyclic tetraadenylate (cA4) to
CC       endonucleolytically degrade linear RNA; when cA4 levels decrease the
CC       RNase activity of Csx1 is abrogated. {ECO:0000269|PubMed:30232454}.
CC   -!- ACTIVITY REGULATION: The RNase activity is stimulated by cA4.
CC       {ECO:0000269|PubMed:30232454}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:30232454, ECO:0000305|Ref.3}.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated Csx1 family.
CC       {ECO:0000305}.
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DR   EMBL; AE006641; AAK41626.1; -; Genomic_DNA.
DR   PIR; C90296; C90296.
DR   RefSeq; WP_009991619.1; NC_002754.1.
DR   PDB; 2I71; X-ray; 1.70 A; A/B=1-377.
DR   PDBsum; 2I71; -.
DR   AlphaFoldDB; Q97YD5; -.
DR   SMR; Q97YD5; -.
DR   STRING; 273057.SSO1389; -.
DR   EnsemblBacteria; AAK41626; AAK41626; SSO1389.
DR   GeneID; 44130246; -.
DR   KEGG; sso:SSO1389; -.
DR   PATRIC; fig|273057.12.peg.1397; -.
DR   eggNOG; arCOG03433; Archaea.
DR   HOGENOM; CLU_695624_0_0_2; -.
DR   InParanoid; Q97YD5; -.
DR   OMA; KPDEIYI; -.
DR   PhylomeDB; Q97YD5; -.
DR   EvolutionaryTrace; Q97YD5; -.
DR   Proteomes; UP000001974; Chromosome.
DR   GO; GO:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR   GO; GO:0051607; P:defense response to virus; IEA:UniProtKB-KW.
DR   Gene3D; 1.10.3740.10; -; 1.
DR   InterPro; IPR027419; CRISPR-assoc_Csx1_C.
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   1: Evidence at protein level;
KW   3D-structure; Antiviral defense; Endonuclease; Hydrolase; Nuclease;
KW   Reference proteome.
FT   CHAIN           1..377
FT                   /note="CRISPR system endoribonuclease Csx1"
FT                   /id="PRO_0000418436"
FT   STRAND          2..10
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          18..22
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          25..31
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           32..39
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          43..50
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           51..57
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           64..79
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          85..88
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          95..97
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           100..117
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          119..128
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           133..152
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          156..162
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          172..175
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          177..184
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           186..198
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   TURN            202..207
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           212..224
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           228..233
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           237..248
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          252..255
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          260..263
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           267..279
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           280..282
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           288..298
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           301..314
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           326..328
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           341..344
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   TURN            345..347
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   TURN            350..352
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          354..358
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   STRAND          361..365
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           367..369
FT                   /evidence="ECO:0007829|PDB:2I71"
FT   HELIX           370..376
FT                   /evidence="ECO:0007829|PDB:2I71"
SQ   SEQUENCE   377 AA;  42929 MW;  B309EE3D233BC286 CRC64;
     MASIVFSTIG NPKGYQKVTY EIDGEKFESN VSVLALRDLL KVDKTVVILG ISVADVYNCK
     YADYRSCKEC IIQNSKNDLG ISESYVVAPN VYQKFKGKPD HYFTYIYYHS LRILEKEGIN
     EVFIDTTHGI NYMGVLAKEA IQLAVSAYAA KSEKEVKVSL YNSDPVGKDV SDTVKLHEIE
     AIKISPLSGL KYVTYQILNK DKNFFNKIFS DSVNAIPRFA TALDNGLFIY LSEKDSSLHL
     KRLEDDLSKD PLLTPSENEI NVVYKDMKYA LSHALFYVIS RFSGNVDLDT LRHYAETYAD
     KVTRAIIENE VDKIEKYQMG SERKLLGEYM KVEGKGFDKR ILYAHGGLPY AGTYVYKEKD
     KVYVTYGDKI DEIERQI