AC   MF_01684;
DC   Protein; auto
TR   HAMAP; MF_01684; -; 1; level=0
XX
Names: Salvage_MtnN
XX
ID   MTNN
DE   RecName: Full=5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase;
DE            Short=MTA/SAH nucleosidase;
DE            Short=MTAN;
DE            EC=3.2.2.9;
DE   AltName: Full=5'-deoxyadenosine nucleosidase;
DE            Short=DOA nucleosidase;
DE            Short=dAdo nucleosidase;
DE   AltName: Full=5'-methylthioadenosine nucleosidase;
DE            Short=MTA nucleosidase;
DE   AltName: Full=S-adenosylhomocysteine nucleosidase;
DE            Short=AdoHcy nucleosidase;
DE            Short=SAH nucleosidase;
DE            Short=SRH nucleosidase;
GN   Name=mtnN;
XX
case <OC:Enterobacterales>
CC   -!- FUNCTION: Catalyzes the irreversible cleavage of the glycosidic bond in
CC       both 5'-methylthioadenosine (MTA) and S-adenosylhomocysteine
CC       (SAH/AdoHcy) to adenine and the corresponding thioribose, 5'-
CC       methylthioribose and S-ribosylhomocysteine, respectively. Also cleaves
CC       5'-deoxyadenosine, a toxic by-product of radical S-adenosylmethionine
CC       (SAM) enzymes, into 5-deoxyribose and adenine. Thus, is required for in
CC       vivo function of the radical SAM enzymes biotin synthase and lipoic
CC       acid synthase, that are inhibited by 5'-deoxyadenosine accumulation.
else
CC   -!- FUNCTION: Catalyzes the irreversible cleavage of the glycosidic bond in
CC       both 5'-methylthioadenosine (MTA) and S-adenosylhomocysteine
CC       (SAH/AdoHcy) to adenine and the corresponding thioribose, 5'-
CC       methylthioribose and S-ribosylhomocysteine, respectively. Also cleaves
CC       5'-deoxyadenosine, a toxic by-product of radical S-adenosylmethionine
CC       (SAM) enzymes, into 5-deoxyribose and adenine.
end case
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H2O + S-adenosyl-L-homocysteine = adenine + S-(5-deoxy-D-
CC         ribos-5-yl)-L-homocysteine; Xref=Rhea:RHEA:17805, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16708, ChEBI:CHEBI:57856, ChEBI:CHEBI:58195; EC=3.2.2.9;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H2O + S-methyl-5'-thioadenosine = 5-(methylsulfanyl)-D-ribose
CC         + adenine; Xref=Rhea:RHEA:13617, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16708, ChEBI:CHEBI:17509, ChEBI:CHEBI:78440; EC=3.2.2.9;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=5'-deoxyadenosine + H2O = 5-deoxy-D-ribose + adenine;
CC         Xref=Rhea:RHEA:29859, ChEBI:CHEBI:15377, ChEBI:CHEBI:16708,
CC         ChEBI:CHEBI:17319, ChEBI:CHEBI:149540; EC=3.2.2.9;
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:29860;
CC   -!- PATHWAY: Amino-acid biosynthesis; L-methionine biosynthesis via salvage
CC       pathway; S-methyl-5-thio-alpha-D-ribose 1-phosphate from S-methyl-5'-
CC       thioadenosine (hydrolase route): step 1/2.
case <OC:Enterobacterales>
CC   -!- SUBUNIT: Homodimer.
end case
CC   -!- SIMILARITY: Belongs to the PNP/UDP phosphorylase family. MtnN
CC       subfamily.
XX
DR   Pfam; PF01048; PNP_UDP_1; 1; trigger=no
DR   NCBIfam; TIGR01704; MTA/SAH-Nsdase; 1; trigger=no
XX
KW   Amino-acid biosynthesis
KW   Hydrolase
KW   Methionine biosynthesis
XX
GO   GO:0008782; F:adenosylhomocysteine nucleosidase activity
GO   GO:0008930; F:methylthioadenosine nucleosidase activity
GO   GO:0019284; P:L-methionine salvage from S-adenosylmethionine
case <OC:Enterobacterales>
GO   GO:0046124; P:purine deoxyribonucleoside catabolic process
end case
XX
FT   From: MTNN_ECOLI (P0AF12)
FT   BINDING         173..174
FT                   /ligand="substrate"
FT   Condition: M-[ED]
FT   ACT_SITE        12
FT                   /note="Proton acceptor"
FT   Condition: E
FT   ACT_SITE        197
FT                   /note="Proton donor"
FT   Condition: D
FT   BINDING         78
FT                   /ligand="substrate"
FT   Condition: [GA]
FT   BINDING         152
FT                   /ligand="substrate"
FT   Condition: [IVML]
XX
Size: 221-251;
Related: None;
Template: P0AF12; O32028; Q9R4A1;
Scope:
 Bacteria
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: None
XX
# Revision 1.23 2023/06/01
//