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Literature summary extracted from
- tryptophan synthase uses an atypical mechanism to achieve substrate specificity (2016), Biochemistry, 55, 7043-7046 .
Cloned(Commentary)
| EC Number | Cloned (Comment) | Organism |
|---|---|---|
| 4.2.1.122 | gene trpS, recombinant expression in Escherichia coli | Pyrococcus furiosus |
Protein Variants
| EC Number | Protein Variants | Comment | Organism |
|---|---|---|---|
| 4.2.1.122 | additional information | usage of directed evolution to engineer TrpB from Pyrococcus furiosus (PfTrpB) to retain activity in the absence of its TrpA partner. Further engineering of this stand-alone enzyme achieves tha catalysis the of efficient beta-substitution of L-threonine (Thr), yielding (2S,3S)-beta-methyltryptophan (beta-MeTrp) in a single step | Pyrococcus furiosus |
KM Value [mM]
| EC Number | KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|---|
| 4.2.1.20 | 0.02 | - |
1-C-(indol-3-yl)glycerol 3-phosphate | cosubstrate L-serine, pH 8.0, temperature not specified in the publication | Pyrococcus furiosus |  |
| 4.2.1.20 | 0.6 | - |
L-serine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 1.3 | - |
L-threonine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 1.4 | - |
1-C-(indol-3-yl)glycerol 3-phosphate | cosubstrate L-threonine, pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
Natural Substrates/ Products (Substrates)
| EC Number | Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 4.2.1.122 | L-serine + indole | Pyrococcus furiosus | Ser and IGP react with a coupling efficiency of over 99% and only trace indole is released into solution by cells | L-tryptophan + H2O | - |
? | |
| 4.2.1.122 | L-threonine + indole | Pyrococcus furiosus | only 17% of the indole that is released from the alpha-subunit goes on to form beta-MeTrp, demonstrating that the release of indole is decoupled from product formation. Thr binds non-covalently to the isolated beta-subunit, indicating that the beta-methyl group hinders entry into the catalytic cycle. The beta-methyl of Thr causes a steric clash that destabilizes the E(Aex1) intermediate | (2S,3S)-beta-methyltryptophan + H2O | - |
? | |
| 4.2.1.122 | additional information | Pyrococcus furiosus | the rate of Thr deamination by PfTrpS is 8.5fold faster than with Ser, competitive with the rate of beta-substitution. Substrate differentiation mechanism of the enzyme, molecular dynamics simulations analysis, overview | ? | - |
? | |
Organism
| EC Number | Organism | UniProt | Comment | Textmining |
|---|---|---|---|---|
| 4.2.1.20 | Pyrococcus furiosus | Q8U093 | - |
- |
| 4.2.1.20 | Pyrococcus furiosus ATCC 43587 | Q8U093 | - |
- |
| 4.2.1.122 | Pyrococcus furiosus | - |
- |
- |
Substrates and Products (Substrate)
| EC Number | Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 4.2.1.20 | L-serine + 1-C-(indol-3-yl)glycerol 3-phosphate | - |
Pyrococcus furiosus | L-tryptophan + D-glyceraldehyde 3-phosphate + H2O | - |
? | |
| 4.2.1.20 | L-serine + 1-C-(indol-3-yl)glycerol 3-phosphate | - |
Pyrococcus furiosus ATCC 43587 | L-tryptophan + D-glyceraldehyde 3-phosphate + H2O | - |
? | |
| 4.2.1.20 | L-threonine + 1-C-(indol-3-yl)glycerol 3-phosphate | - |
Pyrococcus furiosus | (2S,3S)-beta-methyltryptophan + D-glyceraldehyde 3-phosphate + H2O | - |
? | |
| 4.2.1.20 | L-threonine + 1-C-(indol-3-yl)glycerol 3-phosphate | - |
Pyrococcus furiosus ATCC 43587 | (2S,3S)-beta-methyltryptophan + D-glyceraldehyde 3-phosphate + H2O | - |
? | |
| 4.2.1.20 | additional information | native tryptophan synthase can also catalyze a productive reaction with L-threonine, leading to (2S,3S)-beta-methyltryptophan. Substitution occurs in vitro with a 3.4fold higher catalytic efficiency for Ser over Thr using saturating indole. Threonine binds efficiently but decreases the affinity for indole and disrupts the allosteric signaling that regulates the catalytic cycle | Pyrococcus furiosus | ? | - |
? | |
| 4.2.1.20 | additional information | native tryptophan synthase can also catalyze a productive reaction with L-threonine, leading to (2S,3S)-beta-methyltryptophan. Substitution occurs in vitro with a 3.4fold higher catalytic efficiency for Ser over Thr using saturating indole. Threonine binds efficiently but decreases the affinity for indole and disrupts the allosteric signaling that regulates the catalytic cycle | Pyrococcus furiosus ATCC 43587 | ? | - |
? | |
| 4.2.1.122 | L-serine + indole | L-serine is the preferred substrate | Pyrococcus furiosus | L-tryptophan + H2O | - |
? | |
| 4.2.1.122 | L-serine + indole | Ser and IGP react with a coupling efficiency of over 99% and only trace indole is released into solution by cells | Pyrococcus furiosus | L-tryptophan + H2O | - |
? | |
| 4.2.1.122 | L-threonine + indole | - |
Pyrococcus furiosus | (2S,3S)-beta-methyltryptophan + H2O | - |
? | |
| 4.2.1.122 | L-threonine + indole | only 17% of the indole that is released from the alpha-subunit goes on to form beta-MeTrp, demonstrating that the release of indole is decoupled from product formation. Thr binds non-covalently to the isolated beta-subunit, indicating that the beta-methyl group hinders entry into the catalytic cycle. The beta-methyl of Thr causes a steric clash that destabilizes the E(Aex1) intermediate | Pyrococcus furiosus | (2S,3S)-beta-methyltryptophan + H2O | - |
? | |
| 4.2.1.122 | additional information | the rate of Thr deamination by PfTrpS is 8.5fold faster than with Ser, competitive with the rate of beta-substitution. Substrate differentiation mechanism of the enzyme, molecular dynamics simulations analysis, overview | Pyrococcus furiosus | ? | - |
? | |
| 4.2.1.122 | additional information | beta-substitution occurs in vitro with a 3.4fold higher catalytic efficiency for Ser over Thr using saturating indole, despite over 82000fold preference for Ser in direct competition using IGP. When the reaction is conducted with a 1000fold molar excess of Thr over Ser, only Trp is observed, with no trace of beta-MeTrp. Atypical mechanism of specificity: Thr binds efficiently but decreases the affinity for indole and disrupts the allosteric signaling that regulates the catalytic cycle | Pyrococcus furiosus | ? | - |
? | |
Synonyms
| EC Number | Synonyms | Comment | Organism |
|---|---|---|---|
| 4.2.1.20 | TrpB1 | beta subunit | Pyrococcus furiosus |
| 4.2.1.122 | PfTrpS | - |
Pyrococcus furiosus |
| 4.2.1.122 | TRPS | - |
Pyrococcus furiosus |
| 4.2.1.122 | tryptophan synthase | - |
Pyrococcus furiosus |
Temperature Optimum [°C]
| EC Number | Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
|---|---|---|---|---|
| 4.2.1.122 | 75 | - |
assay at | Pyrococcus furiosus |
Turnover Number [1/s]
| EC Number | Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|---|
| 4.2.1.20 | 0.61 | - |
L-threonine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 1 | - |
L-serine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
General Information
| EC Number | General Information | Comment | Organism |
|---|---|---|---|
| 4.2.1.122 | additional information | product binding site analysis | Pyrococcus furiosus |
| 4.2.1.122 | physiological function | tryptophan synthase (TrpS) catalyzes the final steps in the biosynthesis of L-tryptophan from L-serine (Ser) and indole-3-glycerol phosphate (IGP). Native TrpS can also catalyze a productive reaction with L-threonine (Thr), leading to (2S,3S)-beta-methyltryptophan | Pyrococcus furiosus |
kcat/KM [mM/s]
| EC Number | kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
|---|---|---|---|---|---|---|
| 4.2.1.20 | 0.46 | - |
1-C-(indol-3-yl)glycerol 3-phosphate | cosubstrate L-threonine, pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 0.47 | - |
L-threonine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 1.6 | - |
L-serine | pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
| 4.2.1.20 | 50 | - |
1-C-(indol-3-yl)glycerol 3-phosphate | cosubstrate L-serine, pH 8.0, temperature not specified in the publication | Pyrococcus furiosus | |
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