ID   XNI_ECOL6               Reviewed;         251 AA.
AC   Q8FEF2;
DT   21-AUG-2007, integrated into UniProtKB/Swiss-Prot.
DT   24-NOV-2009, sequence version 2.
DT   03-AUG-2022, entry version 99.
DE   RecName: Full=Flap endonuclease Xni {ECO:0000255|HAMAP-Rule:MF_01192};
DE            Short=FEN {ECO:0000255|HAMAP-Rule:MF_01192};
DE            EC=3.1.-.- {ECO:0000255|HAMAP-Rule:MF_01192};
GN   Name=xni {ECO:0000255|HAMAP-Rule:MF_01192};
GN   Synonyms=ygdG {ECO:0000255|HAMAP-Rule:MF_01192}; OrderedLocusNames=c3366;
OS   Escherichia coli O6:H1 (strain CFT073 / ATCC 700928 / UPEC).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=199310;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=CFT073 / ATCC 700928 / UPEC;
RX   PubMed=12471157; DOI=10.1073/pnas.252529799;
RA   Welch R.A., Burland V., Plunkett G. III, Redford P., Roesch P., Rasko D.,
RA   Buckles E.L., Liou S.-R., Boutin A., Hackett J., Stroud D., Mayhew G.F.,
RA   Rose D.J., Zhou S., Schwartz D.C., Perna N.T., Mobley H.L.T.,
RA   Donnenberg M.S., Blattner F.R.;
RT   "Extensive mosaic structure revealed by the complete genome sequence of
RT   uropathogenic Escherichia coli.";
RL   Proc. Natl. Acad. Sci. U.S.A. 99:17020-17024(2002).
CC   -!- FUNCTION: Has flap endonuclease activity. During DNA replication, flap
CC       endonucleases cleave the 5'-overhanging flap structure that is
CC       generated by displacement synthesis when DNA polymerase encounters the
CC       5'-end of a downstream Okazaki fragment. {ECO:0000255|HAMAP-
CC       Rule:MF_01192}.
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01192};
CC       Note=Binds 2 Mg(2+) per subunit. Only one magnesium ion has a direct
CC       interaction with the protein, the other interactions are indirect.
CC       {ECO:0000255|HAMAP-Rule:MF_01192};
CC   -!- COFACTOR:
CC       Name=K(+); Xref=ChEBI:CHEBI:29103;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01192};
CC       Note=Binds 1 K(+) per subunit. The potassium ion strongly increases the
CC       affinity for DNA. {ECO:0000255|HAMAP-Rule:MF_01192};
CC   -!- SIMILARITY: Belongs to the Xni family. {ECO:0000255|HAMAP-
CC       Rule:MF_01192}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAN81813.1; Type=Erroneous initiation; Note=Extended N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; AE014075; AAN81813.1; ALT_INIT; Genomic_DNA.
DR   RefSeq; WP_001296330.1; NC_004431.1.
DR   AlphaFoldDB; Q8FEF2; -.
DR   SMR; Q8FEF2; -.
DR   STRING; 199310.c3366; -.
DR   EnsemblBacteria; AAN81813; AAN81813; c3366.
DR   KEGG; ecc:c3366; -.
DR   eggNOG; COG0258; Bacteria.
DR   HOGENOM; CLU_004675_1_2_6; -.
DR   Proteomes; UP000001410; Chromosome.
DR   GO; GO:0017108; F:5'-flap endonuclease activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0000287; F:magnesium ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0030955; F:potassium ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0033567; P:DNA replication, Okazaki fragment processing; IEA:UniProtKB-UniRule.
DR   CDD; cd09898; H3TH_53EXO; 1.
DR   HAMAP; MF_01192; Xni; 1.
DR   InterPro; IPR020046; 5-3_exonucl_a-hlix_arch_N.
DR   InterPro; IPR002421; 5-3_exonuclease.
DR   InterPro; IPR036279; 5-3_exonuclease_C_sf.
DR   InterPro; IPR020045; DNA_polI_H3TH.
DR   InterPro; IPR038969; FEN.
DR   InterPro; IPR008918; HhH2.
DR   InterPro; IPR029060; PIN-like_dom_sf.
DR   InterPro; IPR022895; Xni.
DR   PANTHER; PTHR42646; PTHR42646; 1.
DR   Pfam; PF01367; 5_3_exonuc; 1.
DR   Pfam; PF02739; 5_3_exonuc_N; 1.
DR   SMART; SM00475; 53EXOc; 1.
DR   SMART; SM00279; HhH2; 1.
DR   SUPFAM; SSF47807; SSF47807; 1.
DR   SUPFAM; SSF88723; SSF88723; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Endonuclease; Hydrolase; Magnesium; Metal-binding; Nuclease;
KW   Potassium.
FT   CHAIN           1..251
FT                   /note="Flap endonuclease Xni"
FT                   /id="PRO_0000297863"
FT   DOMAIN          160..249
FT                   /note="5'-3' exonuclease"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   REGION          184..189
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         104
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         171
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         172
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         180
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         182
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         185
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
SQ   SEQUENCE   251 AA;  28135 MW;  5213D6ED8CE6A4A0 CRC64;
     MAVHLLIVDA LNLIRRIHAV QGSPCVETCQ HALDQLIMHS QPTHAVAVFD DENRSSGWRH
     QRLPDYKAGR PPMPEELHNE MPALRAAFEQ RGVPCWSASG NEADDLAATL AVKVTQAGHQ
     ATIVSTDKGY CQLLSPTLRI RDYFQKRWLD APFIDKEFGV QPQQLPDYWG LAGISSSKVP
     GVAGIGPKSA TQLLVEFQSL EGIYENLDAV AEKWRKKLET HKEMAFLCRD IARLQTDLHI
     DGNLQQLRLV R