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Literature summary for 5.4.3.6 extracted from
- Understanding which residues of the active site and loop structure of a tyrosine aminomutase define its mutase and lyase activities (2018), Biochemistry, 57, 3503-3514 .
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| recombinant expression of wild-type and mutant enzymes | Oryza sativa |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| H109S | site-directed mutagenesis, a single loop mutant | Oryza sativa |
| K113N/E114Q/F115L | site-directed mutagenesis, substrate specificity compared to wild-type | Oryza sativa |
| M92E/N93D/T95A/T97I | site-directed mutagenesis, substrate specificity compared to wild-type | Oryza sativa |
| additional information | homology modeling of wild-type enzyme OsTAM and OsTAM mutant enzymes using the phenylalanine aminomutase (PAM) structure from Taxus canadensis with PDB ID 3NZ4 as template. Exchanging the active residues of OsTAM, Y125C and N446K for those in a phenylalanine aminomutase Taxus canadensis PAM alters its substrate specificity from tyrosine to phenylalanine | Oryza sativa |
| N446K | site-directed mutagenesis, the mutant shows increased activity with phenylalanine and halogenated phenylalanine substrates compared to the wild-type enzyme | Oryza sativa |
| N446K/H109S | site-directed mutagenesis, a joint active site/loop mutant | Oryza sativa |
| N93D/T95A/T97I/G106A/A107C/A108S/H109S | site-directed mutagenesis, substrate specificity compared to wild-type | Oryza sativa |
| T95A/T97I/F115L | site-directed mutagenesis, almost inactive mutant | Oryza sativa |
| T95A/T97I/H109S | site-directed mutagenesis, substrate specificity compared to wild-type | Oryza sativa |
| T95A/T97I/H109S/F115L | site-directed mutagenesis, almost inactive mutant | Oryza sativa |
| Y125C | site-directed mutagenesis, the mutant shows altered activity with phenylalanine and halogenated phenylalanine substrates compared to the wild-type enzyme | Oryza sativa |
| Y125C/N446K | site-directed mutagenesis, the mutant shows altered activity with phenylalanine and halogenated phenylalanine substrates compared to the wild-type enzyme | Oryza sativa |
| Y125C/N446K/T95A/T97I/F115L | site-directed mutagenesis, almost inactive mutant | Oryza sativa |
| Y125C/N446K/T95A/T97I/H109S | site-directed mutagenesis, substrate specificity compared to wild-type | Oryza sativa |
| Y125C/N446K/T95A/T97I/H109S/F115L | site-directed mutagenesis, almost inactive mutant | Oryza sativa |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| L-tyrosine | Oryza sativa | - |
3-amino-3-(4-hydroxyphenyl)propanoate | - |
? |  |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Oryza sativa | - |
- |
- |
Reaction
| Reaction | Comment | Organism | Reaction ID |
|---|---|---|---|
| L-tyrosine = 3-amino-3-(4-hydroxyphenyl)propanoate | the 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) group in the enzyme's active site N-alkylates the NH2 of the alpha-amino acid substrates and promotes the removal of an intermediary NH2-MIO adduct. Concomitant removal of a beta-proton from the substrate (NH2-MIO adduct) by a catalytic tyrosine yields an acrylate intermediate. The aminomutase reaction continues by vicinal reprotonation and reamination at the alpha- and beta-carbons, respectively, of the acrylate to produce the beta-amino acid. Mechanism of MIO-dependent aminomutase, overview | Oryza sativa |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| 4-bromo-L-phenylalanine | - |
Oryza sativa | 4-bromo-L-beta-phenylalanine | - |
? | |
| 4-chloro-L-phenylalanine | - |
Oryza sativa | 4-chloro-L-beta-phenylalanine | - |
? | |
| 4-fluoro-L-phenylalanine | - |
Oryza sativa | 4-fluoro-L-beta-phenylalanine | - |
? | |
| L-phenylalanine | 3% relative to the activity with L-tyrosine of wild-type enzyme | Oryza sativa | L-beta-phenylalanine | - |
? | |
| L-tyrosine | - |
Oryza sativa | 3-amino-3-(4-hydroxyphenyl)propanoate | - |
? | |
| L-tyrosine | wild-type OsTAM from Oryza sativa preferentially isomerizes (2S)-alpha-tyrosine to (3R)-beta-tyrosine with an enantioselectivity (94% ee) | Oryza sativa | 3-amino-3-(4-hydroxyphenyl)propanoate | - |
? | |
| additional information | the 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) group in the enzyme's active site N-alkylates the NH2 of the alpha-amino acid substrates and promotes the removal of an intermediary NH2-MIO adduct. Concomitant removal of a beta-proton from the substrate (NH2-MIO adduct) by a catalytic tyrosine yields an acrylate intermediate. The aminomutase reaction continues by vicinal reprotonation and reamination at the alpha- and beta-carbons, respectively, of the acrylate to produce the beta-amino acid. Autocatalysis of the 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) cofactor through cyclization of (A/T/S)-Ser-Gly residues within the active site | Oryza sativa | ? | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| 3,5-dihydro-5-methylidene-4H-imidazol-4-one-dependent aminomutase | - |
Oryza sativa |
| MIO-dependent aminomutase | - |
Oryza sativa |
| More | cf. EC 5.4.3.10 | Oryza sativa |
| OsTAM | - |
Oryza sativa |
| TAM | - |
Oryza sativa |
Cofactor
| Cofactor | Comment | Organism | Structure |
|---|---|---|---|
| 3,5-dihydro-5-methylidene-4H-imidazol-4-one | i.e. MIO, dependent on. The MIO group is formed by condensation and cyclization of backbone residues of an (A, T, or S)-Ser-Gly triad in the active site. The MIO N-alkylates the NH2 of the alpha-amino acid substrates and promotes the removal of an intermediary NH2-MIO adduct. Concomitant removal of a beta-proton from the substrate (NH2-MIO adduct) by a catalytic tyrosine yields an acrylate intermediate. Autocatalysis of the 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO) cofactor through cyclization of (A/T/S)-Ser-Gly residues within the active site, overview | Oryza sativa | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| evolution | MIO-dependent aminomutases belong to a class I lyase-like family, in which the MIO group is formed by condensation and cyclization of backbone residues of an (A, T, or S)-Ser-Gly triad in the active site. The active sites of rice tyrosine aminomutase and Taxus canadensis phenylalanine aminomutase share a high degree of sequence identity, which may in part explain why OsTAM also converts phenylalanine to beta-phenylalanine | Oryza sativa |
| additional information | homology modeling of wild-type enzyme OsTAM and OsTAM mutant enzymes using the phenylalanine aminomutase structure from Taxus canadensis with PDB ID 3NZ4 as template. The active site of enzyme TAM has a flexible inner loop region | Oryza sativa |
| physiological function | MIO (3,5-dihydro-5-methylidene-4H-imidazol-4-one)-dependent aminomutases (AMs) are involved in the the biosynthetic pathways of biologically active, medicinal compounds in plants and microorganisms | Oryza sativa |
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