EC Number | Cloned (Comment) | Organism |
---|---|---|
4.2.1.42 | expression in Escherichia coli | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.42 | expression in Escherichia coli | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
4.2.1.156 | expression in Escherichia coli | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | Crystallization (Comment) | Organism |
---|---|---|
4.2.1.42 | structures of the wild type enzyme complexed with L-lyxarohydroxamate, and of the K197A mutant complexed with L-glucarate. Residue Lys 197 functions as the galactarate-specific base and His 328 functions as the L-talarate-specific base | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.42 | three different crystal forms are grown by hanging drop vapor diffusion at room temperature: (1) selenomethionine (SeMet)-substituted wild type enzyme, (2) wild-type enzyme complexed with Mg2+ and L-lyxarohydroxamate, and (3) the K197A mutant enzyme complexed with Mg2+ and L-glucarate | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
4.2.1.156 | structures of the wild type enzyme complexed with L-lyxarohydroxamate, and of the K197A mutant complexed with L-glucarate. Residue Lys 197 functions as the galactarate-specific base and His 328 functions as the L-talarate-specific base | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | Protein Variants | Comment | Organism |
---|---|---|---|
4.2.1.42 | H328A | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.42 | H328N | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.42 | K197A | inactive mutant enzyme, the structure of the K197A mutant enzyme complexed with Mg2+ and L-glucarate is determined by molecular replacement using the SeMet-substituted STM3697 structure as the search model | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
4.2.1.42 | K197A | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.156 | H328A | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.156 | H328N | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.156 | K197A | inactive. Mutation totally eliminates both the dehydration and epimerization activities using both L-talarate and galactarate | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|---|
4.2.1.42 | 0.33 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium | |
4.2.1.42 | 0.33 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | |
4.2.1.156 | 0.23 | - |
L-talarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | Metals/Ions | Comment | Organism | Structure |
---|---|---|---|---|
4.2.1.42 | Mg2+ | required | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | |
4.2.1.42 | Mg2+ | required. Ligands are residues Asp226, Glu252, and Glu278 | Salmonella enterica subsp. enterica serovar Typhimurium | |
4.2.1.156 | Mg2+ | required. Ligands are residues Asp226, Glu252, and Glu278 | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | Organism | UniProt | Comment | Textmining |
---|---|---|---|---|
4.2.1.42 | Salmonella enterica subsp. enterica serovar Typhimurium | Q8ZL58 | bifunctional L-talarate/galactarate dehydratase, activites of EC 4.2.1.42 and EC 4.2.1.156 | - |
4.2.1.42 | Salmonella enterica subsp. enterica serovar Typhimurium ATCC 700720 | Q8ZL58 | bifunctional L-talarate/galactarate dehydratase, activites of EC 4.2.1.42 and EC 4.2.1.156 | - |
4.2.1.42 | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | Q8ZL58 | - |
- |
4.2.1.156 | Salmonella enterica subsp. enterica serovar Typhimurium | Q8ZL58 | bifunctional L-talarate/galactarate dehydratase, activites of ECs 4.2.1.42 and 4.2.1.156 | - |
4.2.1.156 | Salmonella enterica subsp. enterica serovar Typhimurium ATCC 700720 | Q8ZL58 | bifunctional L-talarate/galactarate dehydratase, activites of ECs 4.2.1.42 and 4.2.1.156 | - |
EC Number | Purification (Comment) | Organism |
---|---|---|
4.2.1.42 | - |
Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
EC Number | Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|---|
4.2.1.42 | galactarate | galactarate i.e. (2R,3S,4R,5S)-2,3,4,5-tetrahydroxyhexanedioate. The enzyme also catalyzes dehydration of L-talarate. The dehydration of L-talarate is accompanied by competing epimerization to galactarate. Little epimerization to L-talarate is observed in the dehydration of galactarate. On the basis of (1) structures of the wild type enzyme complexed with L-lyxarohydroxamate, an analogue of the enolate intermediate, and of the K197A mutant complexed with L-glucarate, a substrate for exchange of the R-proton, and (2) incorporation of solvent deuterium into galactarate in competition with dehydration, it is concluded that Lys197 functions as the galactarate-specific base and His328 functions as the L-talarate-specific base. The epimerization of L-talarate to galactarate that competes with dehydration can be rationalized by partitioning of the enolate intermediate between dehydration (departure of the 3-OH group catalyzed by the conjugate acid of His328) and epimerization (protonation on C2 by the conjugate acid of Lys197). Only galactarate and L-talarate are completely dehydrated by the enzyme. No other acid sugar results in detectable turnover | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | 5-dehydro-4-deoxy-D-glucarate + H2O | - |
? | |
4.2.1.42 | galactarate | - |
Salmonella enterica subsp. enterica serovar Typhimurium | (2R,3S)-2,3-dihydroxy-5-oxohexanedioate + H2O | - |
? | |
4.2.1.42 | galactarate | - |
Salmonella enterica subsp. enterica serovar Typhimurium ATCC 700720 | (2R,3S)-2,3-dihydroxy-5-oxohexanedioate + H2O | - |
? | |
4.2.1.156 | L-talarate | - |
Salmonella enterica subsp. enterica serovar Typhimurium | 5-dehydro-4-deoxy-D-glucarate + H2O | the dehydration of L-talarate is accompanied by competing epimerization to galactarate | ? | |
4.2.1.156 | L-talarate | - |
Salmonella enterica subsp. enterica serovar Typhimurium ATCC 700720 | 5-dehydro-4-deoxy-D-glucarate + H2O | the dehydration of L-talarate is accompanied by competing epimerization to galactarate | ? |
EC Number | Synonyms | Comment | Organism |
---|---|---|---|
4.2.1.42 | STM3697 | - |
Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.42 | STM3697 | - |
Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
4.2.1.156 | STM3697 | - |
Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|---|
4.2.1.42 | 25 | - |
assay at | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
EC Number | Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|---|
4.2.1.42 | 3.6 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium | |
4.2.1.42 | 3.6 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | |
4.2.1.156 | 2.1 | - |
L-talarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|---|
4.2.1.42 | 8 | - |
assay at | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 |
EC Number | General Information | Comment | Organism |
---|---|---|---|
4.2.1.42 | physiological function | disruption of gene STM3697 diminishes, but does not eliminate, the ability of the organism to utilize galactarate as carbon source. Disruption eliminates the ability to grow on L-talarate | Salmonella enterica subsp. enterica serovar Typhimurium |
4.2.1.156 | physiological function | Salmonella typhimurium LT2 can utilize L-talarate as carbon source. Insertional disruption of the gene talarate dehydratase abolishes this phenotype. The disruption also diminishes, but does not eliminate, the ability of the organism to utilize galactarate as carbon source | Salmonella enterica subsp. enterica serovar Typhimurium |
EC Number | kcat/KM Value [1/mMs-1] | kcat/KM Value Maximum [1/mMs-1] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|---|
4.2.1.42 | 0.11 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium | |
4.2.1.42 | 11 | - |
galactarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium str. LT2 | |
4.2.1.156 | 9.1 | - |
L-talarate | pH 8.0, 25°C | Salmonella enterica subsp. enterica serovar Typhimurium |