5C0O

m1A58 tRNA methyltransferase mutant - Y78A

5C0O の概要

• エントリーDOI: 10.2210/pdb5c0o/pdb
• 関連するPDBエントリー: 2PWY
• 分子名称: tRNA (adenine(58)-N(1))-methyltransferase TrmI, S-ADENOSYLMETHIONINE, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: transferase, trmi, m1a
• 由来する生物種: Thermus thermophilus (strain HB27 / ATCC BAA-163 / DSM 7039)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 115885.84

構造登録者

Degut, C.,Ponchon, L.,Folly-Klan, M.,Barraud, P.,Tisne, C. (登録日: 2015-06-12, 公開日: 2015-07-08, 最終更新日: 2024-01-10)

主引用文献

Degut, C.,Ponchon, L.,Folly-Klan, M.,Barraud, P.,Tisne, C.
The m1A58 modification in eubacterial tRNA: An overview of tRNA recognition and mechanism of catalysis by TrmI.
Biophys.Chem., 210:27-34, 2016

PubMed Abstract: The enzymes of the TrmI family catalyze the formation of the m(1)A58 modification in tRNA. We previously solved the crystal structure of the Thermus thermophilus enzyme and conducted a biophysical study to characterize the interaction between TrmI and tRNA. TrmI enzymes are active as a tetramer and up to two tRNAs can bind to TrmI simultaneously. In this paper, we present the structures of two TrmI mutants (D170A and Y78A). These residues are conserved in the active site of TrmIs and their mutations result in a dramatic alteration of TrmI activity. Both structures of TrmI mutants revealed the flexibility of the N-terminal domain that is probably important to bind tRNA. The structure of TrmI Y78A catalytic domain is unmodified regarding the binding of the SAM co-factor and the conformation of residues potentially interacting with the substrate adenine. This structure reinforces the previously proposed role of Y78, i.e. stabilize the conformation of the A58 ribose needed to hold the adenosine in the active site. The structure of the D170A mutant shows a flexible active site with one loop occupying in part the place of the co-factor and the second loop moving at the entrance to the active site. This structure and recent data confirms the central role of D170 residue binding the amino moiety of SAM and the exocyclic amino group of adenine. Possible mechanisms for methyl transfer are then discussed.

PubMed: 26189113
DOI: 10.1016/j.bpc.2015.06.012

実験手法

X-RAY DIFFRACTION (2.62 Å)