1U7X

crystal structure of a mutant M. jannashii tyrosyl-tRNA synthetase specific for O-methyl-tyrosine

1U7X の概要

• エントリーDOI: 10.2210/pdb1u7x/pdb
• 関連するPDBエントリー: 1U7D
• 分子名称: Tyrosyl-tRNA synthetase, POTASSIUM ION (2 entities in total)
• 機能のキーワード: rossmann fold, ligase
• 由来する生物種: Methanocaldococcus jannaschii
• 細胞内の位置: Cytoplasm: Q57834
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 71656.26

構造登録者

Zhang, Y.,Wang, L.,Schultz, P.G.,Wilson, I.A. (登録日: 2004-08-04, 公開日: 2005-05-24, 最終更新日: 2023-08-23)

主引用文献

Zhang, Y.,Wang, L.,Schultz, P.G.,Wilson, I.A.
Crystal structures of apo wild-type M. jannaschii tyrosyl-tRNA synthetase (TyrRS) and an engineered TyrRS specific for O-methyl-L-tyrosine.
Protein Sci., 14:1340-1349, 2005

PubMed Abstract: The Methanococcus jannaschii tRNA(Tyr)/TyrRS pair has been engineered to incorporate unnatural amino acids into proteins in E. coli. To reveal the structural basis for the altered specificity of mutant TyrRS for O-methyl-L-tyrosine (OMeTyr), the crystal structures for the apo wild-type and mutant M. jannaschii TyrRS were determined at 2.66 and 3.0 A, respectively, for comparison with the published structure of TyrRS complexed with tRNA(Tyr) and substrate tyrosine. A large conformational change was found for the anticodon recognition loop 257-263 of wild-type TyrRS upon tRNA binding in order to facilitate recognition of G34 of the anticodon loop through pi-stacking and hydrogen bonding interactions. Loop 133-143, which is close to the tRNA acceptor stem-binding site, also appears to be stabilized by interaction with the tRNA(Tyr). Binding of the substrate tyrosine results in subtle and cooperative movements of the side chains within the tyrosine-binding pocket. In the OMeTyr-specific mutant synthetase structure, the signature motif KMSKS loop and acceptor stem-binding loop 133-143 were surprisingly ordered in the absence of bound ATP and tRNA. The active-site mutations result in altered hydrogen bonding and steric interactions which favor binding of OMeTyr over L-tyrosine. The structure of the mutant and wild-type TyrRS now provide a basis for generating new active-site libraries to evolve synthetases specific for other unnatural amino acids.

PubMed: 15840835
DOI: 10.1110/ps.041239305

実験手法

X-RAY DIFFRACTION (3 Å)