KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Km-values are determined for wild-type and mutant forms of yeast tRNAPhe | Escherichia coli | |
0.78 | - |
tRNA uridine55 | in yeast tRNAPhe, pH 8.0, 37°C | Escherichia coli |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Escherichia coli | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
tRNA uridine55 | activity is determined with yeast tRNAPhe (wild-type and mutants). A 17 base oligoribonucleotide analog of the T-arm is equivalent to intact native tRNA as a substrate for pseudouridine 55 synthase. The structures and activities of mutant tRNAs and T-arms are used to analyze substrate recognition by pseudouridine 55 synthase. The 17-mer T-arm is an excellent substrate for the synthase, while disruption of the stem structure of the 17-mer T-arm eliminates activity. Kinetic data on tRNA mutants lacking single T-stem base pairs indicate that only the 53:61 base pair, which maintains the 7 base loop size, is essential for activity. The identities of individual bases in the stem are unimportant provided base pairing is intact. A major function of the T-stem appears to be the maintainence of a stable stem-loop structure and proper presentation of the T-loop to pseudouridine 55 synthase. The 7 base T-loop can be expanded or contracted by 1 base and still retains activity, albeit with a 30fold reduction in kcat. Kinetic analysis of T-loop mutants reveals the requirement for uridine54, uridine55, and adenine58, and a preference for cytosine over uridine at position 56 | Escherichia coli | tRNA pseudouridine55 | - |
? |
Synonyms | Comment | Organism |
---|---|---|
tRNA pseudouridine 55 synthase | - |
Escherichia coli |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Escherichia coli |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | turnover numbers are determined for wild-type and mutant forms of yeast tRNAPhe. The 7 base T-loop can be expanded or contracted by 1 base and still retains activity, albeit with a 30fold reduction in kcat | Escherichia coli | |
0.24 | - |
tRNA uridine55 | in yeast tRNAPhe, pH 8.0, 37°C | Escherichia coli |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8 | - |
assay at | Escherichia coli |