MTNN_ECO45
ID MTNN_ECO45 Reviewed; 232 AA.
AC B7MBE2;
DT 28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT 24-MAR-2009, sequence version 1.
DT 03-AUG-2022, entry version 76.
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, ECO:0000269|PubMed:31950558};
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, ECO:0000303|PubMed:31950558};
GN OrderedLocusNames=ECS88_0170;
OS Escherichia coli O45:K1 (strain S88 / ExPEC).
OC Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC Enterobacteriaceae; Escherichia.
OX NCBI_TaxID=585035;
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=S88 / ExPEC;
RX PubMed=19165319; DOI=10.1371/journal.pgen.1000344;
RA Touchon M., Hoede C., Tenaillon O., Barbe V., Baeriswyl S., Bidet P.,
RA Bingen E., Bonacorsi S., Bouchier C., Bouvet O., Calteau A., Chiapello H.,
RA Clermont O., Cruveiller S., Danchin A., Diard M., Dossat C., Karoui M.E.,
RA Frapy E., Garry L., Ghigo J.M., Gilles A.M., Johnson J., Le Bouguenec C.,
RA Lescat M., Mangenot S., Martinez-Jehanne V., Matic I., Nassif X., Oztas S.,
RA Petit M.A., Pichon C., Rouy Z., Ruf C.S., Schneider D., Tourret J.,
RA Vacherie B., Vallenet D., Medigue C., Rocha E.P.C., Denamur E.;
RT "Organised genome dynamics in the Escherichia coli species results in
RT highly diverse adaptive paths.";
RL PLoS Genet. 5:E1000344-E1000344(2009).
RN [2]
RP FUNCTION, CATALYTIC ACTIVITY, AND BIOPHYSICOCHEMICAL PROPERTIES.
RC STRAIN=ATCC 25922 / DSM 1103 / NCIB 12210 / ExPEC;
RX PubMed=31950558; DOI=10.1111/mmi.14459;
RA North J.A., Wildenthal J.A., Erb T.J., Evans B.S., Byerly K.M., Gerlt J.A.,
RA Tabita F.R.;
RT "A bifunctional salvage pathway for two distinct S-adenosylmethionine by-
RT products that is widespread in bacteria, including pathogenic Escherichia
RT coli.";
RL Mol. Microbiol. 113:923-937(2020).
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 (PubMed:31950558). Thus,
CC is required for in vivo function of the radical SAM enzymes biotin
CC synthase and lipoic acid synthase, that are inhibited by 5'-
CC deoxyadenosine accumulation (By similarity). Part of a bifunctional
CC DHAP-shunt salvage pathway for SAM by-products (PubMed:31950558).
CC {ECO:0000255|HAMAP-Rule:MF_01684, ECO:0000269|PubMed:31950558}.
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 Evidence={ECO:0000255|HAMAP-Rule:MF_01684,
CC ECO:0000269|PubMed:31950558};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:17806;
CC Evidence={ECO:0000269|PubMed:31950558};
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 Evidence={ECO:0000255|HAMAP-Rule:MF_01684,
CC ECO:0000269|PubMed:31950558};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:13618;
CC Evidence={ECO:0000269|PubMed:31950558};
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 ECO:0000269|PubMed:31950558};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:29860;
CC Evidence={ECO:0000255|HAMAP-Rule:MF_01684,
CC ECO:0000269|PubMed:31950558};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=5.4 uM for S-adenosyl-L-homocysteine
CC {ECO:0000269|PubMed:31950558};
CC KM=0.83 uM for S-methyl-5'-thioadenosine
CC {ECO:0000269|PubMed:31950558};
CC KM=4.7 uM for 5'-deoxyadenosine {ECO:0000269|PubMed:31950558};
CC KM=93 uM for adenine {ECO:0000269|PubMed:31950558};
CC Note=kcat is 84 sec(-1) with S-adenosyl-L-homocysteine as substrate.
CC kcat is 150 sec(-1) with S-methyl-5'-thioadenosine as substrate. kcat
CC is 57 sec(-1) with 5'-deoxyadenosine as substrate. kcat is 0.24 sec(-
CC 1) with adenine as substrate. {ECO:0000269|PubMed:31950558};
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}.
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DR EMBL; CU928161; CAR01535.1; -; Genomic_DNA.
DR RefSeq; WP_000689844.1; NC_011742.1.
DR AlphaFoldDB; B7MBE2; -.
DR SMR; B7MBE2; -.
DR EnsemblBacteria; CAR01535; CAR01535; ECS88_0170.
DR GeneID; 66671551; -.
DR KEGG; ecz:ECS88_0170; -.
DR HOGENOM; CLU_031248_2_2_6; -.
DR OMA; DQFVHSK; -.
DR UniPathway; UPA00904; UER00871.
DR Proteomes; UP000000747; Chromosome.
DR GO; GO:0005737; C:cytoplasm; IEA:UniProt.
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:0019509; P:L-methionine salvage from methylthioadenosine; IEA:UniProtKB-UniPathway.
DR GO; GO:0019284; P:L-methionine salvage from S-adenosylmethionine; IEA:UniProtKB-UniRule.
DR GO; GO:0046124; P:purine deoxyribonucleoside catabolic process; IEA:UniProtKB-UniRule.
DR Gene3D; 3.40.50.1580; -; 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 Pfam; PF01048; PNP_UDP_1; 1.
DR SUPFAM; SSF53167; SSF53167; 1.
DR TIGRFAMs; TIGR01704; MTA/SAH-Nsdase; 1.
PE 1: Evidence at protein level;
KW Amino-acid biosynthesis; Hydrolase; Methionine biosynthesis.
FT CHAIN 1..232
FT /note="5'-methylthioadenosine/S-adenosylhomocysteine
FT nucleosidase"
FT /id="PRO_1000187417"
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; 24354 MW; 9B1FF9BEC39D4F2C CRC64;
MKIGIIGAME EEVTLLRDKI ENRQTISLGG CEIYTGQLNG TEVALLKSGI GKVAAALGAT
LLLEHCKPDV IINTGSAGGL APTLKVGDIV VSDEARYHDA DVTAFGYEYG QLPGCPAGFK
ADDKLIAAAE ACIAELNLNA VRGLIVSGDA FINGSVGLAK IRHNFPQAIA VEMEATAIAH
VCHNFNVPFV VVRAISDVAD QQSHLSFDEF LAVAAKQSSL MVESLVQKLA HG
