ID   MTNN_SALAR              Reviewed;         232 AA.
AC   A9MPK2;
DT   20-JAN-2009, integrated into UniProtKB/Swiss-Prot.
DT   05-FEB-2008, sequence version 1.
DT   02-SEP-2026, entry version 90.
DE   RecName: Full=5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=MTA/SAH nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=MTAN {ECO:0000255|HAMAP-Rule:MF_01684};
DE            EC=3.2.2.9 {ECO:0000255|HAMAP-Rule:MF_01684};
DE   AltName: Full=5'-deoxyadenosine nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=DOA nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=dAdo nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE   AltName: Full=5'-methylthioadenosine nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=MTA nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE   AltName: Full=S-adenosylhomocysteine nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=AdoHcy nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=SAH nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
DE            Short=SRH nucleosidase {ECO:0000255|HAMAP-Rule:MF_01684};
GN   Name=mtnN {ECO:0000255|HAMAP-Rule:MF_01684};
GN   OrderedLocusNames=SARI_02797;
OS   Salmonella arizonae (strain ATCC BAA-731 / CDC346-86 / RSK2980).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Enterobacterales; Enterobacteriaceae; Salmonella.
OX   NCBI_TaxID=41514;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-731 / CDC346-86 / RSK2980;
RG   The Salmonella enterica serovar Arizonae Genome Sequencing Project;
RA   McClelland M., Sanderson E.K., Porwollik S., Spieth J., Clifton W.S.,
RA   Fulton R., Chunyan W., Wollam A., Shah N., Pepin K., Bhonagiri V., Nash W.,
RA   Johnson M., Thiruvilangam P., Wilson R.;
RL   Submitted (NOV-2007) to the EMBL/GenBank/DDBJ databases.
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.
CC       {ECO:0000255|HAMAP-Rule:MF_01684}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=S-adenosyl-L-homocysteine + H2O = S-(5-deoxy-D-ribos-5-yl)-L-
CC         homocysteine + adenine; Xref=Rhea:RHEA:17805, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16708, ChEBI:CHEBI:57856, ChEBI:CHEBI:58195; EC=3.2.2.9;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01684};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=S-methyl-5'-thioadenosine + H2O = 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         Evidence={ECO:0000255|HAMAP-Rule:MF_01684};
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         Evidence={ECO:0000255|HAMAP-Rule:MF_01684};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:29860;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01684};
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. {ECO:0000255|HAMAP-
CC       Rule:MF_01684}.
CC   -!- SUBUNIT: Homodimer. {ECO:0000255|HAMAP-Rule:MF_01684}.
CC   -!- SIMILARITY: Belongs to the PNP/UDP phosphorylase family. MtnN
CC       subfamily. {ECO:0000255|HAMAP-Rule:MF_01684}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; CP000880; ABX22645.1; -; Genomic_DNA.
DR   AlphaFoldDB; A9MPK2; -.
DR   SMR; A9MPK2; -.
DR   STRING; 41514.SARI_02797; -.
DR   KEGG; ses:SARI_02797; -.
DR   HOGENOM; CLU_031248_2_2_6; -.
DR   UniPathway; UPA00904; UER00871.
DR   Proteomes; UP000002084; Chromosome.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
DR   GO; GO:0008782; F:adenosylhomocysteine nucleosidase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0008930; F:methylthioadenosine nucleosidase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0046124; P:purine deoxyribonucleoside catabolic process; IEA:UniProtKB-UniRule.
DR   CDD; cd09008; MTAN; 1.
DR   FunFam; 3.40.50.1580:FF:000001; MTA/SAH nucleosidase family protein; 1.
DR   Gene3D; 3.40.50.1580; Nucleoside phosphorylase domain; 1.
DR   HAMAP; MF_01684; Salvage_MtnN; 1.
DR   InterPro; IPR010049; MTA_SAH_Nsdase.
DR   InterPro; IPR000845; Nucleoside_phosphorylase_d.
DR   InterPro; IPR035994; Nucleoside_phosphorylase_sf.
DR   NCBIfam; TIGR01704; MTA_SAH-Nsdase; 1.
DR   NCBIfam; NF004079; PRK05584.1; 1.
DR   PANTHER; PTHR46832; 5'-METHYLTHIOADENOSINE/S-ADENOSYLHOMOCYSTEINE NUCLEOSIDASE; 1.
DR   PANTHER; PTHR46832:SF1; 5'-METHYLTHIOADENOSINE_S-ADENOSYLHOMOCYSTEINE NUCLEOSIDASE; 1.
DR   Pfam; PF01048; PNP_UDP_1; 1.
DR   SUPFAM; SSF53167; Purine and uridine phosphorylases; 1.
PE   3: Inferred from homology;
KW   Amino-acid biosynthesis; Hydrolase; Methionine biosynthesis;
KW   Reference proteome.
FT   CHAIN           1..232
FT                   /note="5'-methylthioadenosine/S-adenosylhomocysteine
FT                   nucleosidase"
FT                   /id="PRO_0000359327"
FT   ACT_SITE        12
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   ACT_SITE        197
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         78
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         152
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         173..174
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
SQ   SEQUENCE   232 AA;  24588 MW;  CE8253A3A2B6C14F CRC64;
     MKIGIIGAME EEVTLLRDKI ENRQTLTLGG CEIYTGQLNG TDVALLKSGI GKVAAALGAT
     LLLEHCKPDV IINTGSAGGL ASTLKVGDIV VSDEARYHDA DVTAFGYEYG QLPGCPAGFK
     ADDKLIAAAE YCIRELNLNA VRGLIVSGDA FINGSVGLAK IRHNFPNAVA VEMEATAIAH
     VCYNFKVPFV VVRAISDVAD QQSHLNFDEF LAVAAKQSTL MVETLVQKLA HG
//