EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
  2.1.1.207 | more |
in addition to a pyrimidine at position 34, the enzyme requires the presence of N6-(isopentenyl)-2-methylthioadenosine (ms2i6A) at position 37 as a positive identity determinant. Modification i6A, produced by MiaA, is enough to promote recognition of the substrate tRNAs by TrmL. Recognition of an amber codon by the supP suppressor, which is a mutant tRNALeu CmAA carrying the A35U change in the anticodon, is impaired if the suppressor lacks the 2'-O-methylation at the wobble position |
Escherichia coli |
? |
- |
? |
| 2.1.1.207 | more |
anticodon stem-loop minihelices with an extension of 2 base pairs are the minimal substrate for EcTrmL methylation. A35 is a key residue for TrmL recognition, while A36-A37-A38 are important either via direct interaction with TrmL or due to the necessity for prior isopentenylation (i6) at A37. In addition, TrmL only methylates pyrimidines but not purine residues at the wobble position, and the 20-O-methylation relies on prior N6-isopentenyladenosine modification at position 37. tRNALeuCAA and tRNALeuUAA isoacceptors are the only two RNA substrates of TrmL. i6A37 is sufficient to restore 20-O-methylation at C34 of EctRNALeuCAA transcripts in vitro. TrmL activity is sensitive to the modified base at position 37, a defect in synthesis of ms2i6A37 at position 37, leads to the loss of 20-O-methylation at C/U 34 at tRNALeuCAA and tRNALeuUAA isoacceptors.16 The isopentenyl modification at position 37 of transcribed tRNALeu is sufficient to recruit TrmL for methylation of nucleotides C34/U34. Although the affinity of i6A-Ts-tRNALeu CAA to EcTrmL is lower than for wild-type EctRNALeuCAA, the i6A modification has a consequent effect on the binding strength of tRNA transcripts for EcTrmL |
Escherichia coli |
? |
- |
? |
| 2.1.1.207 | more |
the enzyme TrmL can independently catalyze the methyl transfer from S-adenosyl-L-methionine to tRNALeuCAA and tRNALeuUAA isoacceptors without the involvement of other tRNA-binding proteins. EcTrmL alone can efficiently methylate both tRNALeuCAA and tRNALeuUAA isoacceptors by using in vivo-purified tRNA substrates with certain modifications, but not unmodified tRNALeu |
Escherichia coli |
? |
- |
? |
| 2.1.1.207 | more |
the C/U34m modification occurs in leucine tRNACmAA and tRNAcmnm5UmAA. Both of these leucine tRNA isoacceptors recognize UUA-Leu and UUG-Leu codons, and also carry the i6A37 tRNA modification that assists in the optimal decoding of the Leu codons during rpoS translation |
Escherichia coli |
? |
- |
- |
| 2.1.1.207 | more |
the enzyme TrmL can independently catalyze the methyl transfer from S-adenosyl-L-methionine to tRNALeuCAA and tRNALeuUAA isoacceptors without the involvement of other tRNA-binding proteins. EcTrmL alone can efficiently methylate both tRNALeuCAA and tRNALeuUAA isoacceptors by using in vivo-purified tRNA substrates with certain modifications, but not unmodified tRNALeu |
Escherichia coli MT102 |
? |
- |
? |
| 2.1.1.207 | S-adenosyl-L-methionine + 5-carboxymethylaminomethyluridine34 in tRNA |
TrmL catalyzes the methyl transfer from SAM to the 2'-OH of the wobble nucleotide in tRNALeu cmnm5UmAA, which decodes codons UUA and UUG in the Phe/Leu mixed box, and tRNALeu CmAA, which reads the UUG codon included in the Leu family box |
Escherichia coli |
S-adenosyl-L-homocysteine + 5-carboxymethylaminomethyl-2'-O-methyluridine34 in tRNA |
o.e. tRNALeucmnm5UmAA |
? |
| 2.1.1.207 | S-adenosyl-L-methionine + 5-carboxymethylaminomethyluridine34 in tRNA |
TrmL catalyzes the methyl transfer from SAM to the 2'-OH of the wobble nucleotide in tRNALeu cmnm5UmAA, which decodes codons UUA and UUG in the Phe/Leu mixed box, and tRNALeu CmAA, which reads the UUG codon included in the Leu family box. The wobble nucleoside in tRNALeu cmnm5UmAA and tRNALeuCmAA is not thiolated. Nevertheless methylation of the 2'-hydroxyl group favors the C3'-endo ribose conformation for all nucleosides, although the effect is more marked with pyrimidines |
Escherichia coli |
S-adenosyl-L-homocysteine + 5-carboxymethylaminomethyl-2'-O-methyluridine34 in tRNA |
o.e. tRNALeucmnm5UmAA |
? |
| 2.1.1.207 | S-adenosyl-L-methionine + 5-carboxymethylaminomethyluridine34 in tRNALeu |
- |
Escherichia coli |
S-adenosyl-L-homocysteine + 5-carboxymethylaminomethyl-2'-O-methyluridine34 in tRNALeu |
- |
? |
| 2.1.1.207 | S-adenosyl-L-methionine + 5-carboxymethylaminomethyluridine34 in tRNALeu |
the enzyme methylates the ribose at the nucleotide 34 wobble position in the two leucyl isoacceptors tRNALeu(CmAA) and tRNALeu(cmnm5UmAA) |
Escherichia coli |
S-adenosyl-L-homocysteine + 5-carboxymethylaminomethyl-2'-O-methyluridine34 in tRNALeu |
- |
? |
| 2.1.1.207 | S-adenosyl-L-methionine + cytidine34 in tRNA |
- |
Escherichia coli |
S-adenosyl-L-homocysteine + 2'-O-methylcytidine34 in tRNA |
- |
? |
