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Annotation rule MF_01281
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General rule information [?]

Accession MF_01281
Dates 7-NOV-2007 (Created)
19-NOV-2019 (Last updated, Version 23)
Name MTA_SAH_deamin
Templates Q9X034 (MTAD_THEMA); Q58936 (DADD_METJA): [Recover all]

Propagated annotation [?]

Identifier, protein and gene names [?]

case <OC:Methanobacteria> or <OC:Methanococci> or <OC:Methanomicrobia> or <OC:Methanopyri>
Protein name
RecName: Full=5'-deoxyadenosine deaminase;
Short=5'-dA deaminase;
AltName: Full=5'-methylthioadenosine deaminase;
Short=MTA deaminase;
AltName: Full=Adenosine deaminase;
AltName: Full=S-adenosylhomocysteine deaminase;
Short=SAH deaminase;
Gene name
Protein name
RecName: Full=5-methylthioadenosine/S-adenosylhomocysteine deaminase;
Short=MTA/SAH deaminase;
Gene name
end case

Comments [?]

case <OC:Methanobacteria> or <OC:Methanococci> or <OC:Methanomicrobia> or <OC:Methanopyri>
Function Catalyzes the deamination of three SAM-derived enzymatic products, namely 5'-deoxyadenosine, S-adenosyl-L-homocysteine, and 5'-methylthioadenosine, to produce the inosine analogs. Can also deaminate adenosine. The preferred substrate for this enzyme is 5'-deoxyadenosine, but all these substrates are efficiently deaminated. Likely functions in a S-adenosyl-L-methionine (SAM) recycling pathway from S-adenosyl-L-homocysteine (SAH) produced from SAM-dependent methylation reactions. May also be involved in the recycling of 5'-deoxyadenosine, whereupon the 5'-deoxyribose moiety of 5'-deoxyinosine is further metabolized to deoxyhexoses used for the biosynthesis of aromatic amino acids in methanogens.
Catalytic activity RHEA:42892: 5'-deoxyadenosine + H(+) + H2O = 5'-deoxyinosine + NH4(+)
PhysiologicalDirection=left-to-right (RHEA:42893)
RHEA:20716: H(+) + H2O + S-adenosyl-L-homocysteine = NH4(+) + S-inosyl-L-homocysteine
PhysiologicalDirection=left-to-right (RHEA:20717)
RHEA:25025: H(+) + H2O + S-methyl-5'-thioadenosine = NH4(+) + S-methyl-5'-thioinosine
PhysiologicalDirection=left-to-right (RHEA:25026)
RHEA:24408: adenosine + H(+) + H2O = inosine + NH4(+)
PhysiologicalDirection=left-to-right (RHEA:24409)
Pathway Amino-acid biosynthesis; S-adenosyl-L-methionine biosynthesis.
Subunit Homotetramer.
Miscellaneous SAH is a product of SAM methyltransferases and is known to be a feedback inhibitor of these enzymes. As a result of this inhibition, organisms have evolved efficient enzymes to metabolize SAH via different pathways. The pathway found in methanogens differs from the canonical pathway, it uses the deamination of S-adenosyl-L-homocysteine to form S-inosyl-L-homocysteine for the regeneration of SAM from S-adenosyl-L-homocysteine. 5'-deoxyadenosine is a radical SAM enzyme reaction product which strongly inhibits radical SAM enzymes. A pathway for removing this product must be present in methanogens where the MTA/SAH nucleosidase which normally metabolizes this compound is absent.
Function Catalyzes the deamination of 5-methylthioadenosine and S-adenosyl-L-homocysteine into 5-methylthioinosine and S-inosyl-L-homocysteine, respectively. Is also able to deaminate adenosine.
Catalytic activity RHEA:20716: H(+) + H2O + S-adenosyl-L-homocysteine = NH4(+) + S-inosyl-L-homocysteine
RHEA:25025: H(+) + H2O + S-methyl-5'-thioadenosine = NH4(+) + S-methyl-5'-thioinosine
end case
Cofactor Zn(2+)
Note: Binds 1 zinc ion per subunit.
Similarity Belongs to the metallo-dependent hydrolases superfamily. MTA/SAH deaminase family.

Keywords [?]

Gene Ontology [?]

case <OC:Methanobacteria> or <OC:Methanococci> or <OC:Methanomicrobia> or <OC:Methanopyri>
GO:0090613; Molecular function: 5'-deoxyadenosine deaminase activity.
GO:0004000; Molecular function: adenosine deaminase activity.
GO:0050270; Molecular function: S-adenosylhomocysteine deaminase activity.
GO:0090614; Molecular function: 5'-methylthioadenosine deaminase activity.
end case

Cross-references [?]

Pfam PF01979; Amidohydro_1; 1;

Features [?]

From: MTAD_THEMA (Q9X034)
Key     From     To       Description   Tag   Condition   FTGroup
METAL     55     55       Zinc; via tele nitrogen     H  
METAL     57     57       Zinc; via tele nitrogen     H  
METAL     200     200       Zinc; via tele nitrogen     H  
METAL     279     279       Zinc     D  
BINDING     84     84       Substrate     E  
BINDING (Optional)     136     136       Substrate     R  
BINDING (Optional)     148     148       Substrate     R  
BINDING     173     173       Substrate     H  
BINDING     203     203       Substrate     E  
BINDING     279     279       Substrate     D  

Additional information [?]

Size range 406-449 amino acids
Related rules None
Fusion None