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Publication Abstract from PubMed

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.

Crystal structure of the two-subunit tRNA m(1)A58 methyltransferase TRM6-TRM61 from Saccharomyces cerevisiae.,Wang M, Zhu Y, Wang C, Fan X, Jiang X, Ebrahimi M, Qiao Z, Niu L, Teng M, Li X Sci Rep. 2016 Sep 1;6:32562. doi: 10.1038/srep32562. PMID:27582183^[4]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.