ID   MTNN_STAAR              Reviewed;         228 AA.
AC   Q6GGA2;
DT   20-JAN-2009, integrated into UniProtKB/Swiss-Prot.
DT   19-JUL-2004, sequence version 1.
DT   04-NOV-2026, entry version 115.
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=SAR1676;
OS   Staphylococcus aureus (strain MRSA252).
OC   Bacteria; Bacillati; Bacillota; Bacilli; Caryophanales; Staphylococcaceae;
OC   Staphylococcus.
OX   NCBI_TaxID=282458;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=MRSA252;
RX   PubMed=15213324; DOI=10.1073/pnas.0402521101;
RA   Holden M.T.G., Feil E.J., Lindsay J.A., Peacock S.J., Day N.P.J.,
RA   Enright M.C., Foster T.J., Moore C.E., Hurst L., Atkin R., Barron A.,
RA   Bason N., Bentley S.D., Chillingworth C., Chillingworth T., Churcher C.,
RA   Clark L., Corton C., Cronin A., Doggett J., Dowd L., Feltwell T., Hance Z.,
RA   Harris B., Hauser H., Holroyd S., Jagels K., James K.D., Lennard N.,
RA   Line A., Mayes R., Moule S., Mungall K., Ormond D., Quail M.A.,
RA   Rabbinowitsch E., Rutherford K.M., Sanders M., Sharp S., Simmonds M.,
RA   Stevens K., Whitehead S., Barrell B.G., Spratt B.G., Parkhill J.;
RT   "Complete genomes of two clinical Staphylococcus aureus strains: evidence
RT   for the rapid evolution of virulence and drug resistance.";
RL   Proc. Natl. Acad. Sci. U.S.A. 101:9786-9791(2004).
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. {ECO:0000255|HAMAP-
CC       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   -!- SIMILARITY: Belongs to the PNP/UDP phosphorylase family. MtnN
CC       subfamily. {ECO:0000255|HAMAP-Rule:MF_01684}.
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DR   EMBL; BX571856; CAG40670.1; -; Genomic_DNA.
DR   RefSeq; WP_000579273.1; NC_002952.2.
DR   AlphaFoldDB; Q6GGA2; -.
DR   SMR; Q6GGA2; -.
DR   KEGG; sar:SAR1676; -.
DR   HOGENOM; CLU_031248_2_2_9; -.
DR   OMA; AAFCMNT; -.
DR   UniPathway; UPA00904; UER00871.
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:0033353; P:L-methionine cycle; IEA:InterPro.
DR   GO; GO:0009164; P:nucleoside catabolic process; IEA:InterPro.
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.
FT   CHAIN           1..228
FT                   /note="5'-methylthioadenosine/S-adenosylhomocysteine
FT                   nucleosidase"
FT                   /id="PRO_0000359366"
FT   ACT_SITE        11
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   ACT_SITE        196
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         77
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         151
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         172..173
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
SQ   SEQUENCE   228 AA;  24534 MW;  C4DC521CFE80BD8D CRC64;
     MIGIIGAMEE EVTILKNKLT QLSEISVAHV KFYTGILKDR EVVITQSGIG KVNAAISTTL
     LINKFKPDII INTGSAGALD ESLNVGDVLI SDDVKYHDAD ATAFGYEYGQ VPQMPVAFQS
     SKPLIEKVSQ VVQQQQLTAK VGLIVSGDSF IGSVEQRQKI KKAFPNAMAV EMEATAIAQT
     CYQFNVPFVV VRAVSDLANG EAEMSFEAFL EKAAVSSSQT VEALVSQL
//