2GJA

Structure of the MnmE G-domain in complex with GDP*AlF4-, Mg2+ and NH4+

2GJA の概要

• エントリーDOI: 10.2210/pdb2gja/pdb
• 関連するPDBエントリー: 1RFL 1XZP 1XZQ 2GJ8 2GJ9
• 分子名称: tRNA modification GTPase trmE, TETRAFLUOROALUMINATE ION, MAGNESIUM ION, ... (6 entities in total)
• 機能のキーワード: g-domain dimer, alpha-beta-sandwich, hydrolase
• 由来する生物種: Escherichia coli BL21(DE3)
• 細胞内の位置: Cytoplasm: P25522
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 38417.28

構造登録者

Scrima, A.,Wittinghofer, A. (登録日: 2006-03-30, 公開日: 2006-07-04, 最終更新日: 2024-02-14)

主引用文献

Scrima, A.,Wittinghofer, A.
Dimerisation-dependent GTPase reaction of MnmE: how potassium acts as GTPase-activating element.
Embo J., 25:2940-2951, 2006

PubMed Abstract: MnmE, a Guanine nucleotide-binding protein conserved between bacteria and man, is involved in the modification of tRNAs. Here we provide biochemical and X-ray structural evidence for a new GTP-hydrolysis mechanism, where the G-domains of MnmE dimerise in a potassium-dependent manner and induce GTP hydrolysis. The structure in the presence of GDP-AlFx and potassium shows how juxtaposition of the subunits induces a conformational change around the nucleotide which reorients the catalytic machinery. A critical glutamate is positioned such as to stabilise or activate the attacking water. Potassium provides a positive charge into the catalytic site in a position analogous to the arginine finger in the Ras-RasGAP system. Mutational studies show that potassium-dependent dimerisation and GTP hydrolysis can be uncoupled and that interaction between the G-domains is a prerequisite for subsequent phosphoryl transfer. We propose a model for the juxtaposition of G-domains in the full-length protein and how it induces conformational changes in the putative tRNA-modification centre.

PubMed: 16763562
DOI: 10.1038/sj.emboj.7601171

実験手法

X-RAY DIFFRACTION (1.85 Å)