ID   PPO1_PHYPO              Reviewed;         163 AA.
AC   Q94702;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-1998, sequence version 3.
DT   25-MAY-2022, entry version 72.
DE   RecName: Full=Intron-encoded endonuclease I-PpoI;
DE            Short=I-Ppo;
DE            EC=3.1.-.-;
OS   Physarum polycephalum (Slime mold).
OC   Eukaryota; Amoebozoa; Evosea; Eumycetozoa; Myxogastria;
OC   Myxogastromycetidae; Physariida; Physaraceae; Physarum.
OX   NCBI_TaxID=5791;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2355911; DOI=10.1128/mcb.10.7.3386-3396.1990;
RA   Muscarella D.E., Ellison E.L., Ruoff B.M., Vogt V.M.;
RT   "Characterization of I-Ppo, an intron-encoded endonuclease that mediates
RT   homing of a group I intron in the ribosomal DNA of Physarum polycephalum.";
RL   Mol. Cell. Biol. 10:3386-3396(1990).
RN   [2]
RP   SEQUENCE REVISION.
RA   Vogt V.M.;
RL   Submitted (AUG-1997) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   X-RAY CRYSTALLOGRAPHY (2.2 ANGSTROMS).
RX   PubMed=9665136; DOI=10.1038/27952;
RA   Flick K.E., Jurica M.S., Monnat R.J. Jr., Stoddard B.L.;
RT   "DNA binding and cleavage by the nuclear intron-encoded homing endonuclease
RT   I-PpoI.";
RL   Nature 394:96-101(1998).
RN   [4]
RP   X-RAY CRYSTALLOGRAPHY (1.93 ANGSTROMS).
RX   PubMed=10581547; DOI=10.1038/70027;
RA   Galburt E.A., Chevalier B., Tang W., Jurica M.S., Flick K.E.,
RA   Monnat R.J. Jr., Stoddard B.L.;
RT   "A novel endonuclease mechanism directly visualized for I-PpoI.";
RL   Nat. Struct. Biol. 6:1096-1099(1999).
RN   [5]
RP   X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS).
RX   PubMed=10891275; DOI=10.1006/jmbi.2000.3874;
RA   Galburt E.A., Chadsey M.S., Jurica M.S., Chevalier B.S., Erho D., Tang W.,
RA   Monnat R.J. Jr., Stoddard B.L.;
RT   "Conformational changes and cleavage by the homing endonuclease I-PpoI: a
RT   critical role for a leucine residue in the active site.";
RL   J. Mol. Biol. 300:877-887(2000).
CC   -!- FUNCTION: Mediates the homing of a group I intron in the ribosomal DNA.
CC       Makes a four-base staggered cut in its ribosomal DNA target sequence.
CC   -!- COFACTOR:
CC       Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
CC   -!- SUBUNIT: Homodimer.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAB65764.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; M38131; AAB65765.1; -; Genomic_DNA.
DR   EMBL; M38131; AAB65764.1; ALT_INIT; Genomic_DNA.
DR   PDB; 1A73; X-ray; 1.80 A; A/B=1-163.
DR   PDB; 1A74; X-ray; 2.20 A; A/B=1-163.
DR   PDB; 1CYQ; X-ray; 1.93 A; A/B=2-163.
DR   PDB; 1CZ0; X-ray; 2.10 A; A/B=2-163.
DR   PDB; 1EVW; X-ray; 3.10 A; A/B/C/D=1-163.
DR   PDB; 1EVX; X-ray; 2.00 A; A/B=2-163.
DR   PDB; 1IPP; X-ray; 2.20 A; A/B=1-163.
DR   PDB; 2O6M; X-ray; 2.30 A; A/B=1-163.
DR   PDBsum; 1A73; -.
DR   PDBsum; 1A74; -.
DR   PDBsum; 1CYQ; -.
DR   PDBsum; 1CZ0; -.
DR   PDBsum; 1EVW; -.
DR   PDBsum; 1EVX; -.
DR   PDBsum; 1IPP; -.
DR   PDBsum; 2O6M; -.
DR   AlphaFoldDB; Q94702; -.
DR   SMR; Q94702; -.
DR   REBASE; 2469; I-PpoI.
DR   EvolutionaryTrace; Q94702; -.
DR   GO; GO:0004519; F:endonuclease activity; IEA:UniProtKB-KW.
DR   GO; GO:0006314; P:intron homing; IEA:UniProtKB-KW.
DR   Gene3D; 3.90.75.10; -; 1.
DR   InterPro; IPR008704; Endonuclease_Zinc-binding_loop.
DR   InterPro; IPR044925; His-Me_finger_sf.
DR   InterPro; IPR044930; Homing_endonuclease_His-Me.
DR   Pfam; PF05551; zf-His_Me_endon; 1.
DR   SUPFAM; SSF54060; SSF54060; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Endonuclease; Hydrolase; Intron homing; Nuclease; Zinc.
FT   CHAIN           1..163
FT                   /note="Intron-encoded endonuclease I-PpoI"
FT                   /id="PRO_0000192788"
FT   HELIX           5..19
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          24..32
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          35..43
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          46..48
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          54..58
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          61..68
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          71..76
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   TURN            77..79
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   HELIX           80..82
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          83..85
FT                   /evidence="ECO:0007829|PDB:1EVW"
FT   STRAND          87..89
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          92..98
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   HELIX           108..110
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          111..115
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   HELIX           116..121
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   HELIX           122..124
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   TURN            128..131
FT                   /evidence="ECO:0007829|PDB:1A73"
FT   STRAND          157..160
FT                   /evidence="ECO:0007829|PDB:1A73"
SQ   SEQUENCE   163 AA;  17789 MW;  A193B6F06B0D8EEF CRC64;
     MALTNAQILA VIDSWEETVG QFPVITHHVP LGGGLQGTLH CYEIPLAAPY GVGFAKNGPT
     RWQYKRTINQ VVHRWGSHTV PFLLEPDNIN GKTCTASHLC HNTRCHNPLH LCWESLDDNK
     GRNWCPGPNG GCVHAVVCLR QGPLYGPGAT VAGPQQRGSH FVV