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HAMAP rule MF_01963

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General rule information [?]

Accession MF_01963
Dates 23-NOV-2011 (Created)
19-SEP-2024 (Last updated, Version 20)
Name MTAP
Scope(s) Bacteria
Archaea
Template(s) Q97W94 (MTAP_SACS2); Q8U4Q8 (MTAP_PYRFU); Q8U2I1 (PNPH_PYRFU); Q9HZK1 (MTIP_PSEAE); [ Recover all ]
Triggered by
case c? <OC:Bacteria> or <OC:Archaea>
HAMAP; MF_01963 (Get profile general information and statistics)
end case

Propagated annotation [?]

Identifier, protein and gene names [?]

case <FT:3=D-x-D> and <FT:7=S> and <FT:8=[AVMI]>
Identifier MTAP
Protein name RecName: Full=S-methyl-5'-thioadenosine phosphorylase;
                 EC=2.4.2.28;
AltName: Full=5'-methylthioadenosine phosphorylase;
                 Short=MTA phosphorylase;
                 Short=MTAP;
Gene name Name=mtnP;
else case <FT:3=N-x-A> and <FT:7=E> and <FT:8=[AVMI]>
Identifier MTIP
Protein name RecName: Full=Probable S-methyl-5'-thioinosine phosphorylase;
                 EC=2.4.2.44;
AltName: Full=5'-methylthioinosine phosphorylase;
                 Short=MTI phosphorylase;
                 Short=MTIP;
else case <FT:3=N-x-A> and <FT:7=E> and not <FT:8=[AVMI]>
Identifier PNPH
Protein name RecName: Full=Probable 6-oxopurine nucleoside phosphorylase;
                 EC=2.4.2.1;
AltName: Full=Purine nucleoside phosphorylase;
                 Short=PNP;
else
Identifier PNPH
Protein name RecName: Full=Purine nucleoside phosphorylase;
                 Short=PNP;
                 EC=2.4.2.1;
end case

Comments [?]

case <FT:3=D-x-D> and <FT:7=S> and <FT:8=[AVMI]>
FUNCTIONCatalyzes the reversible phosphorylation of S-methyl-5'- thioadenosine (MTA) to adenine and 5-methylthioribose-1-phosphate. Involved in the breakdown of MTA, a major by-product of polyamine biosynthesis. Responsible for the first step in the methionine salvage pathway after MTA has been generated from S-adenosylmethionine. Has broad substrate specificity with 6-aminopurine nucleosides as preferred substrates.
CATALYTIC ACTIVITY Reaction=S-methyl-5'-thioadenosine + phosphate = 5-(methylsulfanyl)- alpha-D-ribose 1-phosphate + adenine; Xref=Rhea:RHEA:11852, ChEBI:CHEBI:16708, ChEBI:CHEBI:17509, ChEBI:CHEBI:43474, ChEBI:CHEBI:58533; EC=2.4.2.28;
PATHWAYAmino-acid biosynthesis; L-methionine biosynthesis via salvage pathway; S-methyl-5-thio-alpha-D-ribose 1-phosphate from S-methyl-5'- thioadenosine (phosphorylase route): step 1/1.
SUBUNITHomohexamer. Dimer of a homotrimer.
else case <FT:3=N-x-A> and <FT:7=E> and <FT:8=[AVMI]>
FUNCTIONCatalyzes the reversible phosphorylation of S-methyl-5'- thioinosine (MTI) to hypoxanthine and 5-methylthioribose-1-phosphate. Involved in the breakdown of S-methyl-5'-thioadenosine (MTA), a major by-product of polyamine biosynthesis. Catabolism of (MTA) occurs via deamination to MTI and phosphorolysis to hypoxanthine.
CATALYTIC ACTIVITY Reaction=S-methyl-5'-thioinosine + phosphate = 5-(methylsulfanyl)- alpha-D-ribose 1-phosphate + hypoxanthine; Xref=Rhea:RHEA:30643, ChEBI:CHEBI:17368, ChEBI:CHEBI:43474, ChEBI:CHEBI:48595, ChEBI:CHEBI:58533; EC=2.4.2.44;
PATHWAYPurine metabolism; purine nucleoside salvage.
SUBUNITHomotrimer.
MISCELLANEOUSAlthough this enzyme belongs to the family of MTA phosphorylases based on sequence homology, it has been shown that conserved amino acid substitutions in the substrate binding pocket convert the substrate specificity of this enzyme from 6-aminopurines to 6-oxopurines.
else case <FT:3=N-x-A> and <FT:7=E>
FUNCTIONPurine nucleoside phosphorylase which is highly specific for 6-oxopurine nucleosides. Cleaves guanosine or inosine to respective bases and sugar-1-phosphate molecules. Involved in purine salvage.
CATALYTIC ACTIVITY Reaction=a purine D-ribonucleoside + phosphate = a purine nucleobase + alpha-D-ribose 1-phosphate; Xref=Rhea:RHEA:19805, ChEBI:CHEBI:26386, ChEBI:CHEBI:43474, ChEBI:CHEBI:57720, ChEBI:CHEBI:142355; EC=2.4.2.1;
PATHWAYPurine metabolism; purine nucleoside salvage.
SUBUNITHomohexamer. Dimer of a homotrimer.
MISCELLANEOUSAlthough this enzyme belongs to the family of MTA phosphorylases based on sequence homology, it has been shown that conserved amino acid substitutions in the substrate binding pocket convert the substrate specificity of this enzyme from 6-aminopurines to 6-oxopurines.
else
FUNCTIONPurine nucleoside phosphorylase involved in purine salvage.
CATALYTIC ACTIVITY Reaction=a purine D-ribonucleoside + phosphate = a purine nucleobase + alpha-D-ribose 1-phosphate; Xref=Rhea:RHEA:19805, ChEBI:CHEBI:26386, ChEBI:CHEBI:43474, ChEBI:CHEBI:57720, ChEBI:CHEBI:142355; EC=2.4.2.1;
PATHWAYPurine metabolism; purine nucleoside salvage.
SUBUNITHomohexamer. Dimer of a homotrimer.
MISCELLANEOUSAlthough this enzyme belongs to the family of MTA phosphorylases based on sequence homology, it lacks several conserved amino acids in the substrate binding pocket that confer specificity towards MTA.
end case
SIMILARITYBelongs to the PNP/MTAP phosphorylase family. MTAP subfamily.

Keywords [?]

Glycosyltransferase
Purine salvage
Transferase

Gene Ontology [?]

case <FT:3=D-x-D> and <FT:7=S> and <FT:8=[AVI]>
GO:0017061; Molecular function:S-methyl-5-thioadenosine phosphorylase activity
GO:0019509; Biological process:L-methionine salvage from methylthioadenosine
else; https://www.ebi.ac.uk/QuickGO/term/else
GO:0016763; Molecular function:pentosyltransferase activity
GO:0006166; Biological process:purine ribonucleoside salvage
end case

Cross-references [?]

PROSITE PS01240; PNP_MTAP_2; 1;
Pfam PF01048; PNP_UDP_1; 1;
NCBIfam TIGR01694; MTAP; 1;

Features [?]

From: MTAP_SACS2 (Q97W94)
Key From To Description Tag Condition FTGroup
BINDING 58 59 /ligand="phosphate"
/ligand_id="ChEBI:CHEBI:43474"		 R-[HN]
BINDING 91 92 /ligand="phosphate"
/ligand_id="ChEBI:CHEBI:43474"		 [ST]-A
BINDING 214 216 /ligand="substrate" [DN]-x-[DA]
BINDING 16 16 /ligand="phosphate"
/ligand_id="ChEBI:CHEBI:43474"		 [ST]
BINDING 190 190 /ligand="substrate" M
BINDING 191 191 /ligand="phosphate"
/ligand_id="ChEBI:CHEBI:43474"		 [ST]
From: PNPH_PYRFU (Q8U2I1)
Key From To Description Tag Condition FTGroup
SITE 169 169 /note="Important for substrate specificity" [SE]
SITE 223 223 /note="Important for substrate specificity"

Additional information [?]

Size range 237-355 amino acids
Related rules None
Fusion Nter: None Cter: None



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