ID   MTAP_CIOIN              Reviewed;         280 AA.
AC   F6X2V8;
DT   25-JAN-2012, integrated into UniProtKB/Swiss-Prot.
DT   27-JUL-2011, sequence version 1.
DT   27-MAR-2024, entry version 57.
DE   RecName: Full=S-methyl-5'-thioadenosine phosphorylase {ECO:0000255|HAMAP-Rule:MF_03155};
DE            EC=2.4.2.28 {ECO:0000255|HAMAP-Rule:MF_03155};
DE   AltName: Full=5'-methylthioadenosine phosphorylase {ECO:0000255|HAMAP-Rule:MF_03155};
DE            Short=MTA phosphorylase {ECO:0000255|HAMAP-Rule:MF_03155};
DE            Short=MTAP {ECO:0000255|HAMAP-Rule:MF_03155};
DE            Short=MTAPase {ECO:0000255|HAMAP-Rule:MF_03155};
OS   Ciona intestinalis (Transparent sea squirt) (Ascidia intestinalis).
OC   Eukaryota; Metazoa; Chordata; Tunicata; Ascidiacea; Phlebobranchia;
OC   Cionidae; Ciona.
OX   NCBI_TaxID=7719;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=12481130; DOI=10.1126/science.1080049;
RA   Dehal P., Satou Y., Campbell R.K., Chapman J., Degnan B., De Tomaso A.,
RA   Davidson B., Di Gregorio A., Gelpke M., Goodstein D.M., Harafuji N.,
RA   Hastings K.E., Ho I., Hotta K., Huang W., Kawashima T., Lemaire P.,
RA   Martinez D., Meinertzhagen I.A., Necula S., Nonaka M., Putnam N., Rash S.,
RA   Saiga H., Satake M., Terry A., Yamada L., Wang H.G., Awazu S., Azumi K.,
RA   Boore J., Branno M., Chin-Bow S., DeSantis R., Doyle S., Francino P.,
RA   Keys D.N., Haga S., Hayashi H., Hino K., Imai K.S., Inaba K., Kano S.,
RA   Kobayashi K., Kobayashi M., Lee B.I., Makabe K.W., Manohar C., Matassi G.,
RA   Medina M., Mochizuki Y., Mount S., Morishita T., Miura S., Nakayama A.,
RA   Nishizaka S., Nomoto H., Ohta F., Oishi K., Rigoutsos I., Sano M.,
RA   Sasaki A., Sasakura Y., Shoguchi E., Shin-i T., Spagnuolo A., Stainier D.,
RA   Suzuki M.M., Tassy O., Takatori N., Tokuoka M., Yagi K., Yoshizaki F.,
RA   Wada S., Zhang C., Hyatt P.D., Larimer F., Detter C., Doggett N.,
RA   Glavina T., Hawkins T., Richardson P., Lucas S., Kohara Y., Levine M.,
RA   Satoh N., Rokhsar D.S.;
RT   "The draft genome of Ciona intestinalis: insights into chordate and
RT   vertebrate origins.";
RL   Science 298:2157-2167(2002).
CC   -!- FUNCTION: Catalyzes the reversible phosphorylation of S-methyl-5'-
CC       thioadenosine (MTA) to adenine and 5-methylthioribose-1-phosphate.
CC       Involved in the breakdown of MTA, a major by-product of polyamine
CC       biosynthesis. Responsible for the first step in the methionine salvage
CC       pathway after MTA has been generated from S-adenosylmethionine. Has
CC       broad substrate specificity with 6-aminopurine nucleosides as preferred
CC       substrates. {ECO:0000255|HAMAP-Rule:MF_03155}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=phosphate + S-methyl-5'-thioadenosine = adenine + S-methyl-5-
CC         thio-alpha-D-ribose 1-phosphate; Xref=Rhea:RHEA:11852,
CC         ChEBI:CHEBI:16708, ChEBI:CHEBI:17509, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:58533; EC=2.4.2.28; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_03155};
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 (phosphorylase route): step 1/1. {ECO:0000255|HAMAP-
CC       Rule:MF_03155}.
CC   -!- SUBUNIT: Homotrimer. {ECO:0000255|HAMAP-Rule:MF_03155}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000255|HAMAP-Rule:MF_03155}.
CC       Nucleus {ECO:0000255|HAMAP-Rule:MF_03155}.
CC   -!- SIMILARITY: Belongs to the PNP/MTAP phosphorylase family. MTAP
CC       subfamily. {ECO:0000255|HAMAP-Rule:MF_03155}.
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DR   RefSeq; XP_002131665.1; XM_002131629.4.
DR   RefSeq; XP_018667802.1; XM_018812257.1.
DR   AlphaFoldDB; F6X2V8; -.
DR   SMR; F6X2V8; -.
DR   STRING; 7719.ENSCINP00000005182; -.
DR   eggNOG; KOG3985; Eukaryota.
DR   InParanoid; F6X2V8; -.
DR   UniPathway; UPA00904; UER00873.
DR   Proteomes; UP000008144; Unplaced.
DR   GO; GO:0005829; C:cytosol; IBA:GO_Central.
DR   GO; GO:0005634; C:nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0017061; F:S-methyl-5-thioadenosine phosphorylase activity; IBA:GO_Central.
DR   GO; GO:0019509; P:L-methionine salvage from methylthioadenosine; IBA:GO_Central.
DR   GO; GO:0006166; P:purine ribonucleoside salvage; IEA:UniProtKB-KW.
DR   CDD; cd09010; MTAP_SsMTAPII_like_MTIP; 1.
DR   Gene3D; 3.40.50.1580; Nucleoside phosphorylase domain; 1.
DR   HAMAP; MF_01963; MTAP; 1.
DR   InterPro; IPR010044; MTAP.
DR   InterPro; IPR000845; Nucleoside_phosphorylase_d.
DR   InterPro; IPR035994; Nucleoside_phosphorylase_sf.
DR   InterPro; IPR018099; Purine_phosphorylase-2_CS.
DR   NCBIfam; TIGR01694; MTAP; 1.
DR   PANTHER; PTHR42679; S-METHYL-5'-THIOADENOSINE PHOSPHORYLASE; 1.
DR   PANTHER; PTHR42679:SF2; S-METHYL-5'-THIOADENOSINE PHOSPHORYLASE; 1.
DR   Pfam; PF01048; PNP_UDP_1; 1.
DR   SUPFAM; SSF53167; Purine and uridine phosphorylases; 1.
DR   PROSITE; PS01240; PNP_MTAP_2; 1.
PE   3: Inferred from homology;
KW   Cytoplasm; Glycosyltransferase; Nucleus; Purine salvage;
KW   Reference proteome; Transferase.
FT   CHAIN           1..280
FT                   /note="S-methyl-5'-thioadenosine phosphorylase"
FT                   /id="PRO_0000415116"
FT   BINDING         18
FT                   /ligand="phosphate"
FT                   /ligand_id="ChEBI:CHEBI:43474"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   BINDING         60..61
FT                   /ligand="phosphate"
FT                   /ligand_id="ChEBI:CHEBI:43474"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   BINDING         93..94
FT                   /ligand="phosphate"
FT                   /ligand_id="ChEBI:CHEBI:43474"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   BINDING         196
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   BINDING         197
FT                   /ligand="phosphate"
FT                   /ligand_id="ChEBI:CHEBI:43474"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   BINDING         220..222
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   SITE            178
FT                   /note="Important for substrate specificity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
FT   SITE            233
FT                   /note="Important for substrate specificity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_03155"
SQ   SEQUENCE   280 AA;  30829 MW;  FDA5FC0E8A8A4B58 CRC64;
     MMESGDRQNN KIGIIGGSGL ESIELFTVKD KVNCNTPYGK PSSSLINGTL NGIECVLLSR
     HGDSHDIMPT DVNYRANLYA LKEAGCSIIL ATTACGSLQE ELKPTDFVVI DQFIDRTTKR
     HSTFYDGQNV QMKGVCHIPM RNPFCEKLQN VLLSACNVNN VSCHSKGTMV TIEGPRFSTY
     AESNLFRKWG GSLINMTTVP EVVLANELGM LYAALAMVTD YDCWKEDHAS VNVENVMKTM
     KVNRGNALKV LVSAVEIISK QNLQPDIQLA EKNAKNSVML
//