ID   XNI_SALPA               Reviewed;         251 AA.
AC   Q5PEL3;
DT   21-AUG-2007, integrated into UniProtKB/Swiss-Prot.
DT   24-NOV-2009, sequence version 3.
DT   03-AUG-2022, entry version 79.
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=SPA2836;
OS   Salmonella paratyphi A (strain ATCC 9150 / SARB42).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Salmonella.
OX   NCBI_TaxID=295319;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 9150 / SARB42;
RX   PubMed=15531882; DOI=10.1038/ng1470;
RA   McClelland M., Sanderson K.E., Clifton S.W., Latreille P., Porwollik S.,
RA   Sabo A., Meyer R., Bieri T., Ozersky P., McLellan M., Harkins C.R.,
RA   Wang C., Nguyen C., Berghoff A., Elliott G., Kohlberg S., Strong C., Du F.,
RA   Carter J., Kremizki C., Layman D., Leonard S., Sun H., Fulton L., Nash W.,
RA   Miner T., Minx P., Delehaunty K., Fronick C., Magrini V., Nhan M.,
RA   Warren W., Florea L., Spieth J., Wilson R.K.;
RT   "Comparison of genome degradation in Paratyphi A and Typhi, human-
RT   restricted serovars of Salmonella enterica that cause typhoid.";
RL   Nat. Genet. 36:1268-1274(2004).
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}.
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DR   EMBL; CP000026; AAV78684.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q5PEL3; -.
DR   SMR; Q5PEL3; -.
DR   EnsemblBacteria; AAV78684; AAV78684; SPA2836.
DR   KEGG; spt:SPA2836; -.
DR   HOGENOM; CLU_004675_1_2_6; -.
DR   OMA; WRVDLIP; -.
DR   Proteomes; UP000008185; 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_0000297870"
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;  28178 MW;  17B7426F3EBBB87B CRC64;
     MAAHLLIVDA LNLIRRIHAV QGSPCVETCQ HALDQLIIHS QPTHAVAVFD DDARSSGWRH
     QRLPDYKAGR PPMPDDLHNE MPALRAAFEQ RGVRCWASDG NEADDLAATL ALKVTEAGHQ
     ATIVSTDKGY CQLLSPGLRI RDYFQKRWLD APFIEKEFGV LPRQLPDYWG LAGISSSKVP
     GVAGIGPKSA TQLLIQFQNL EGIYAHLDEV PEKWRKKLET HKEMAFLCRD IARLQTDLHI
     DGNLQQLRLV R