AC   MF_04140;
DC   Protein; auto
TR   HAMAP; MF_04140; -; 1; level=0
XX
Names: FEN_T5
XX
ID   FEN
DE   RecName: Full=Flap endonuclease;
DE            Short=FEN;
DE            EC=3.1.11.-;
DE   AltName: Full=5'-3' exonuclease;
DE   AltName: Full=Exodeoxyribonuclease;
DE            EC=3.1.11.3;
XX
CC   -!- FUNCTION: Catalyzes both the 5'-exonucleolytic and structure-specific
CC       endonucleolytic hydrolysis of DNA branched nucleic acid molecules and
CC       probably plays a role in viral genome replication. Active on flap
CC       (branched duplex DNA containing a free single-stranded 5'-end),
CC       5'overhangs and pseudo-Y structures. The substrates require a free,
CC       single-stranded 5' end, with endonucleolytic hydrolysis occurring at
CC       the junction of double- and single-stranded DNA. This function may be
CC       used for example to trim such branched molecules generated by Okazaki
CC       fragments synthesis during replication.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Exonucleolytic cleavage in the 5'- to 3'-direction to yield
CC         nucleoside 5'-phosphates.; EC=3.1.11.3;
case <FTGroup:2> and <FTGroup:1>
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Name=K(+); Xref=ChEBI:CHEBI:29103;
CC       Note=Binds divalent metal cations, probably Mg(2+). In vitro low metal
CC       concentrations selectively stimulate the endonuclease reaction.
CC       Endonuclease activity is suggested to require only the first cation,
CC       whereas exonuclease activity is suggested to require binding of both.
CC       High pH favors the exonuclase activity whereas low pH favors the
CC       endonuclease activity. Metal ions enhance substrate binding. K(+) is
CC       bound to the H3TH region;
else
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Note=Binds divalent metal cations, probably Mg(2+). In vitro low metal
CC       concentrations selectively stimulate the endonuclease reaction.
CC       Endonuclease activity is suggested to require only the first cation,
CC       whereas exonuclease activity is suggested to require binding of both.
CC       High pH favors the exonuclase activity whereas low pH favors the
CC       endonuclease activity. Metal ions enhance substrate binding
end case
CC   -!- DOMAIN: Three alpha-helices form a helical arch which forms a hole in
CC       the protein and through which the 5' flap of the scissile ssDNA is
CC       threaded.
XX
DR   Pfam; PF01367; 5_3_exonuc; 1; trigger=no
DR   Pfam; PF02739; 5_3_exonuc_N; 1; trigger=no
DR   General; Coiled_coil; -; 0-unlimited; trigger=yes
XX
KW   DNA replication
KW   DNA-binding
KW   Early protein
KW   Endonuclease
KW   Exonuclease
KW   Hydrolase
KW   Metal-binding
KW   Magnesium
KW   Nuclease
case <FTGroup:1>
KW   Potassium
end case
KW   Viral DNA replication
XX
GO   GO:0008409; F:5'-3' exonuclease activity
GO   GO:0017108; F:5'-flap endonuclease activity
GO   GO:0003677; F:DNA binding
GO   GO:0046872; F:metal ion binding
GO   GO:0033567; P:DNA replication, Okazaki fragment processing
GO   GO:0039693; P:viral DNA genome replication
XX
FT   From: FEN_BPT5 (P06229)
FT   CHAIN           Nter..Cter
FT                   /note="Flap endonuclease"
FT   DOMAIN          190..263
FT                   /note="5'-3' exonuclease"
FT   REGION          82..116
FT                   /note="Helical arch"
FT   Condition: Y-K-x*
FT   REGION          188..224
FT                   /note="DNA-binding; H3TH"
FT   Condition: x(2)-[ED]-x*-G-D-x-x-D-x*
FT   BINDING         130
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="1"
FT                   /ligand_note="catalytic"
FT   Condition: D
FT   BINDING         130
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /ligand_note="catalytic"
FT   Group: 2; Condition: D
FT   BINDING         153
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /ligand_note="catalytic"
FT   Group: 2; Condition: D
FT   BINDING         155
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /ligand_note="catalytic"
FT   Group: 2; Condition: D
FT   BINDING         155
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="3"
FT   Condition: D
FT   BINDING         201
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="3"
FT   Condition: D
FT   BINDING         209
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT   Group: 1; Condition: V
FT   BINDING         212
FT                   /ligand="K(+)"
FT                   /ligand_id="ChEBI:CHEBI:29103"
FT   Group: 1; Condition: I
FT   BINDING         83
FT                   /ligand="DNA"
FT                   /ligand_id="ChEBI:CHEBI:16991"
FT   Condition: K
XX
Size: 200-350;
Related: None;
Template: P06229;
Scope:
 Viruses
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.7 2022/11/19
//