2.1.1.207	evolution	the enzyme belongs to the SPOUT tRNA MTase superfamily	737224	
2.1.1.207	evolution	TrmL is a member of the SPOUT superfamily. TrmH, TrmJ and TrmL belong to the SpoU family, and TrmD belongs to the TrmD family. Unlike other transfer RNAs (tRNA)-modifying enzymes from the SPOUT methyltransferase superfamily, the tRNA (Um34/Cm34) methyltransferase TrmL lacks the usual extension domain for tRNA binding and consists only of a SPOUT domain. Domain architectures of SPOUT tRNA MTases and the sequence alignment of TrmLs, overview. TrmL enzymes are widely distributed throughout the bacterial kingdom	-, 736900	
2.1.1.207	evolution	TrmL is a representative protein of SPOUTenzymes, a class of S-adenosyl-L-methionine-dependent methyltransferases that exhibit an unusual fold with a very deep topological knot. TrmL is one of the smallest alpha/beta-knot proteins	719015	
2.1.1.207	malfunction	inactivation of yibK leads to loss of 2'-O-methylation at position 34 in both tRNALeu(CmAA) and tRNALeu(cmnm5UmAA). Loss of YibK methylation reduces the efficiency of codon–wobble base interaction. Inactivation of yibK has no detectable effect on steady-state growth rate, although a distinct disadvantage is noted in multiple-round, mixed-population growth experiments, suggesting that the ability to recover from the stationary phase is impaired. Methylation is restored in vivo by complementing with a recombinant copy of yibK	710552	
2.1.1.207	malfunction	the defect in RpoS translation in the absence of i6A37 prenyl transferase (MiaA) is due to the inability to add the C/U34m modification to UUX-Leu tRNAs	756162	
2.1.1.207	metabolism	modifications at the wobble uridine, U34, of tRNAs reading two degenerate codons ending in purine are complex and result from the activity of two multi-enzyme pathways, the IscSeMnmA and MnmEG pathways, which independently work on positions 2 and 5 of the U34 pyrimidine ring, respectively, and from a third single-step pathway, controlled by TrmL, i.e. YibK, that modifies the 2'-hydroxyl group of the ribose. TrmL occurs as a late step in the maturation of the tRNALeu isoacceptors	719015	
2.1.1.207	metabolism	role of several tRNA modifications on rpoS or hfq expression: 2'-O-methylation of cytidine or uridine, at the wobble position (C/Um), 2-thiouridine at the wobble position (s2U), as well as isopentenyl adenosine 37(i6A37), overview	756162	
2.1.1.207	additional information	the enzyme TrmL functions as a homodimer by using the conserved C-terminal half of the SPOUT domain for catalysis, whereas residues from the less-conserved N-terminal half of the other subunit participate in tRNA recognition. Analysis of the structure of the active site. EcTrmL dimer formation is essential for tRNA recognition. The residue Y142 is critical for maintaining the dimeric form of EcTrmL, which is consistent with its central position at the interface	-, 736900	
2.1.1.207	additional information	TrmL-catalyzed 2'-O-methylation requires its homodimerization. TrmL exhibits a fine-tuned tRNA substrate recognition mechanism. The variable arm of tRNA is not a recognition element for EcTrmL. The anticodon stem of tRNA does not contain recognition elements for EcTrmL	737224	
2.1.1.207	physiological function	the addition of the 2'-O-methylcytidine/uridine 34 (C/U34m) tRNA modification by tRNA (cytidine/uridine-2'O)-ribose methyltransferase L (TrmL) in Escherichia coli requires the presence of the N6-isopentenyl adenosine 37 (i6A37). The C/U34m and s2U34 tRNA modifications are necessary for full proper rpoS translation. Gene trmL is necessary for leucine decoding during RpoS expression. The mechanism of action of the i6A37 tRNA modification on RpoS expression is, at least in part, promotion of efficient UUX-leucine decoding. Possibly the TrmL-catalyzed C/U34m tRNA modification is dispensable for hfq translation, while the MiaA catalyzed i6A37 is necessary for efficient hfq translation	756162	
2.1.1.207	physiological function	TrmL is the prokaryotic methyltransferase that catalyzes the transfer of the methyl group from S-adenosyl-L-methionine to the wobble base of tRNALeuCAA and tRNALeuUAA isoacceptors. This Cm34/Um34 modification affects codon-anticodon interactions and is essential for translational fidelity	737224