ID   XNI_PHOPR               Reviewed;         258 AA.
AC   Q6LN06;
DT   21-AUG-2007, integrated into UniProtKB/Swiss-Prot.
DT   21-AUG-2007, sequence version 2.
DT   03-AUG-2022, entry version 89.
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};
GN   OrderedLocusNames=PBPRA2986;
OS   Photobacterium profundum (strain SS9).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Vibrionales; Vibrionaceae;
OC   Photobacterium.
OX   NCBI_TaxID=298386;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-1253 / SS9;
RX   PubMed=15746425; DOI=10.1126/science.1103341;
RA   Vezzi A., Campanaro S., D'Angelo M., Simonato F., Vitulo N., Lauro F.M.,
RA   Cestaro A., Malacrida G., Simionati B., Cannata N., Romualdi C.,
RA   Bartlett D.H., Valle G.;
RT   "Life at depth: Photobacterium profundum genome sequence and expression
RT   analysis.";
RL   Science 307:1459-1461(2005).
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=CAG21320.1; Type=Erroneous initiation; Note=Extended N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; CR378672; CAG21320.1; ALT_INIT; Genomic_DNA.
DR   RefSeq; WP_041394496.1; NC_006370.1.
DR   AlphaFoldDB; Q6LN06; -.
DR   SMR; Q6LN06; -.
DR   STRING; 298386.PBPRA2986; -.
DR   EnsemblBacteria; CAG21320; CAG21320; PBPRA2986.
DR   KEGG; ppr:PBPRA2986; -.
DR   eggNOG; COG0258; Bacteria.
DR   HOGENOM; CLU_004675_1_2_6; -.
DR   OrthoDB; 1220182at2; -.
DR   Proteomes; UP000000593; Chromosome 1.
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; Reference proteome.
FT   CHAIN           1..258
FT                   /note="Flap endonuclease Xni"
FT                   /id="PRO_0000297865"
FT   DOMAIN          165..254
FT                   /note="5'-3' exonuclease"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   REGION          189..194
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         109
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         176
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         177
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"
FT   BINDING         187
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
FT   BINDING         190
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01192"
SQ   SEQUENCE   258 AA;  28744 MW;  8D4876CC016516A6 CRC64;
     MTIHLVVIDA LNLIRRVHAA QPGEPDVKNT ARVCCQALSK IIKFSEPSHI VAVFDHHGDD
     RGWRAKLLPH YKEGRKPMPP ELQAGMEIIQ DAFMDLGIDS LLSDGDEADD LVATLALKVA
     SRHQQVTIIS TDKGYCQLLS PTLRVRDYFQ QRWLDSPFVE KEYGVKPEQL PDYWGLAGIS
     SSKIPGIPGI GPKAALELLS LYPDLDTILQ AEDLPTKWQK KITKHRESAE ASKKVASLKT
     DLTLGFNLQD IRYLAPSS