AC   MF_01470;
DC   Protein; auto
TR   HAMAP; MF_01470; -; 1; level=0
XX
Names: Cas1
XX
ID   CAS1
DE   RecName: Full=CRISPR-associated endonuclease Cas1;
DE            EC=3.1.-.-;
GN   Name=cas1;
XX
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). Acts as
CC       a dsDNA endonuclease. Involved in the integration of spacer DNA into
CC       the CRISPR cassette.
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035;
CC   -!- SUBUNIT: Homodimer, forms a heterotetramer with a Cas2 homodimer.
CC   -!- SIMILARITY: Belongs to the CRISPR-associated endonuclease Cas1 family.
XX
DR   Pfam; PF01867; Cas_Cas1; 1; trigger=no
DR   NCBIfam; TIGR00287; Cas1; 1; trigger=no
XX
KW   Antiviral defense
KW   DNA-binding
KW   Endonuclease
KW   Hydrolase
KW   Magnesium
KW   Manganese
KW   Metal-binding
KW   Nuclease
XX
GO   GO:0004519; F:endonuclease activity
GO   GO:0046872; F:metal ion binding
GO   GO:0051607; P:defense response to virus
GO   GO:0043571; P:maintenance of CRISPR repeat elements
XX
FT   From: CAS1_PSEAB (Q02ML7)
FT   BINDING         190
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT   Condition: E
FT   BINDING         254
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT   Condition: H
FT   BINDING         268
FT                   /ligand="Mn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29035"
FT   Condition: [DE]
XX
Size: 250-437;
Related: None;
Template: Q02ML7; Q46896;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: <Cas4>; <Reverse transcriptase>
 Cter: None
Duplicate: in ACEPA, PARA1, ACIB4, ACIHW, ACTSZ, ALKMQ, ALLVD, AMMDK, CALBD,
 ANATU, ARCFU, AZOS1, KYRT2, BACTR, BIFAN, BIFDB, CALH1, CALK2, CALKI, CALNY,
 CALOO, CALS8, CHLAA, CHLAD, CHLL2, CHLPD, CHLSY, CHLTE, CHLTF, CHRVO, CLOAI,
 RUMCH, CLOTE, ACET2, CORDI, CORUB, CORUL, COXBN, CROS5, CYAP2, CYAP4, GLOC7,
 DEIGD, DESAP, DESAR, DESAS, DESB2, DESCC, DESHD, DESIS, DESK7, SOLM1, DESRL,
 DESRM, DICD3, DICZ5, MUSP7, DICT6, DICC1, ECOLX, ENTFA, ENTFC, ERWP6, ERWPE,
 EUBR3, FERNB, FIBSS, FILAD, FLESM, FRAAA, FRANO, FRACC, FRATN, FRATU, GEOS0,
 GEOSL, GLUDA, HALH1, HALLT, HALWC, HELMI, HERA2, IGNH4, KITSK, LACRR, LEGPL,
 LEPBD, LEPIN, LISMO, MANSM, MARHT, MARM1, MEGEL, MEIRD, MEISD, META2, METBF,
 METBU, METCG, METHJ, METIM, METLZ, METMA, METMM, METPE, METRM, METS3, METST,
 METV3, METVS, MOOTA, MYCBO, MYCTU, MYXXD, NEIGO, NEIL0, NEIME, NITEC, NITEU,
 NITHN, NITSE, NITWC, NITWN, NOSS1, OXAFO, PAEP6, PARDN, PASMU, PECWW, PELPB,
 PELTS, PHOPR, PICTO, PORG3, PORGI, PORGT, PSEAI, PYRAE, PYRHO, PYRYC, RHOCB,
 ALBFT, RHOM4, RHOMR, RHORT, RHORU, RHOVT, ROSCS, ROSS1, SACVD, SALAI, SALET,
 SORC5, SPICD, SPIPL, STRED, STREM, STRG1, STRG3, STRMN, STRMU, STRP1, STRPB,
 STRPC, STRPD, STRPM, STRPZ, STRT1, STRT2, STRTD, STRTN, STRTR, SULAA, SULAC,
 SULIA, SULID, SULIH, SULIM, SULS9, SACS2, SULTO, SYNAS, SYNFM, SYNGF, SYNLT,
 PICP2, SYNWW, SYNY3, THEAB, THECD, THEID, THEM3, THEM4, PYRNV, THEPJ, THES4,
 THESO, THET1, THET8, THETC, THETG, THEXL, THEYD, THISH, TRURR, METAR, UNCTG,
 VEREI, WOLSU, XANAP, YERPE, ZUNPS, ZYMMN, ZYMMT
Plasmid: in ACEP3, ACEPA, ACICJ, ALLVD, CYAP2, CYAP4, GLOC7, DEIGD, DEIPM,
 DESVH, DESVR, DESVV, HALH1, HALLT, HALMA, HALVD, HERA2, ILYPC, LEGPL, MEISD,
 PHOPR, ALBFT, RHOM4, RHOMR, STRRO, PICP2, SYNY3, THET2, THET8, THETG, ZYMMN,
 ZYMMT
Comments: Frequently duplicated, there are many subfamiles, this one
 however is the master family. Sometimes found fused after Cas4 or a
 reverse transcriptase domain. One of the METRM (Q2FPW6) is missing
 residues predicted to be involved in metal-binding and is atypical.
XX
# Revision 1.32 2023/12/07
//