ID   MTNN_PSET1              Reviewed;         235 AA.
AC   Q3ILJ7;
DT   20-JAN-2009, integrated into UniProtKB/Swiss-Prot.
DT   08-NOV-2005, sequence version 1.
DT   02-SEP-2026, entry version 105.
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=PSHAa0547;
OS   Pseudoalteromonas translucida (strain TAC 125).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Alteromonadales; Pseudoalteromonadaceae; Pseudoalteromonas.
OX   NCBI_TaxID=326442;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=TAC 125;
RX   PubMed=16169927; DOI=10.1101/gr.4126905;
RA   Medigue C., Krin E., Pascal G., Barbe V., Bernsel A., Bertin P.N.,
RA   Cheung F., Cruveiller S., D'Amico S., Duilio A., Fang G., Feller G., Ho C.,
RA   Mangenot S., Marino G., Nilsson J., Parrilli E., Rocha E.P.C., Rouy Z.,
RA   Sekowska A., Tutino M.L., Vallenet D., von Heijne G., Danchin A.;
RT   "Coping with cold: the genome of the versatile marine Antarctica bacterium
RT   Pseudoalteromonas haloplanktis TAC125.";
RL   Genome Res. 15:1325-1335(2005).
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; CR954246; CAI85635.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q3ILJ7; -.
DR   SMR; Q3ILJ7; -.
DR   STRING; 326442.PSHAa0547; -.
DR   KEGG; pha:PSHAa0547; -.
DR   eggNOG; COG0775; Bacteria.
DR   HOGENOM; CLU_031248_2_2_6; -.
DR   BioCyc; PHAL326442:PSHA_RS02665-MONOMER; -.
DR   UniPathway; UPA00904; UER00871.
DR   Proteomes; UP000006843; Chromosome I.
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: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;
KW   Reference proteome.
FT   CHAIN           1..235
FT                   /note="5'-methylthioadenosine/S-adenosylhomocysteine
FT                   nucleosidase"
FT                   /id="PRO_0000359324"
FT   ACT_SITE        12
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   ACT_SITE        198
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         153
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
FT   BINDING         174..175
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01684"
SQ   SEQUENCE   235 AA;  24883 MW;  C8B49E447504C7FB CRC64;
     MNVGIIGAME PEVKILREAM QNPQTLTKAG FTFYTGELAG NTVTLVQSGI GKVASTIATT
     LLIDNFAPDC VINTGSAGGF DPSLNVGDVV ISSEVRHHDV DVTAFGYEIG QVPQMPAGFA
     AHPKLVAAAE QTIAQISDVK TLVGLICTGD IFMCDPIRIE KARSDFPTML AVEMEGASIA
     QTCHTLNTPF VVIRSMSDIA GKESPQSFEE YLETASINSS KMVVALLEKL TAVSL
//