5EQJ: Crystal Structure Of The Two-subunit Trna M1a58 Methyltransferase From Saccharomyces Cerevisiae

The N(1) methylation of adenine at position 58 (m(1)A58) of tRNA is an important post-transcriptional modification, which is vital for maintaining the stability of the initiator methionine tRNAi(Met). In eukaryotes, this modification is performed by the TRM6-TRM61 holoenzyme. To understand the molecular mechanism that underlies the cooperation of TRM6 and TRM61 in the methyl transfer reaction, we determined the crystal structure of TRM6-TRM61 holoenzyme from Saccharomyces cerevisiae in the presence and absence of its methyl donor S-Adenosyl-L-methionine (SAM). In the structures, two TRM6-TRM61 heterodimers assemble as a heterotetramer. Both TRM6 and TRM61 subunits comprise an N-terminal beta-barrel domain linked to a C-terminal Rossmann-fold domain. TRM61 functions as the catalytic subunit, containing a methyl donor (SAM) binding pocket. TRM6 diverges from TRM61, lacking the conserved motifs used for binding SAM. However, TRM6 cooperates with TRM61 forming an L-shaped tRNA binding regions. Collectively, our results provide a structural basis for better understanding the m(1)A58 modification of tRNA occurred in Saccharomyces cerevisiae.
PDB ID: 5EQJDownload
MMDB ID: 143029
PDB Deposition Date: 2015/11/13
Updated in MMDB: 2016/09
Experimental Method:
x-ray diffraction
Resolution: 2.2  Å
Source Organism:
Similar Structures:
Biological Unit for 5EQJ: tetrameric; determined by author and by software (PISA)
Molecular Components in 5EQJ
Label Count Molecule
Proteins (4 molecules)
tRNA (Adenine(58)-n(1))-methyltransferase Non-catalytic Subunit Trm6(Gene symbol: GCD10)
Molecule annotation
tRNA (Adenine(58)-n(1))-methyltransferase Catalytic Subunit Trm61(Gene symbol: GCD14)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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