4B48

Bacterial translation initiation factor IF2 (1-363), complex with GTP

4B48 の概要

• エントリーDOI: 10.2210/pdb4b48/pdb
• 関連するPDBエントリー: 4B3X 4B43 4B44 4B47
• 分子名称: TRANSLATION INITIATION FACTOR IF-2, GUANOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• 機能のキーワード: translation, initiation, gtp hydrolysis mechanism
• 由来する生物種: THERMUS THERMOPHILUS
• 細胞内の位置: Cytoplasm: P48515
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 40742.46

構造登録者

Simonetti, A.,Urzhumtsev, A.,Klaholz, B.P. (登録日: 2012-07-27, 公開日: 2013-05-29, 最終更新日: 2023-12-20)

主引用文献

Simonetti, A.,Marzi, S.,Fabbretti, A.,Hazemann, I.,Jenner, L.,Urzhumtsev, A.,Gualerzi, C.O.,Klaholz, B.P.
Structure of the Protein Core of Translation Initiation Factor 2 in Apo, GTP-Bound and Gdp-Bound Forms
Acta Crystallogr.,Sect.D, 69:925-, 2013

PubMed Abstract: Translation initiation factor 2 (IF2) is involved in the early steps of bacterial protein synthesis. It promotes the stabilization of the initiator tRNA on the 30S initiation complex (IC) and triggers GTP hydrolysis upon ribosomal subunit joining. While the structure of an archaeal homologue (a/eIF5B) is known, there are significant sequence and functional differences in eubacterial IF2, while the trimeric eukaryotic IF2 is completely unrelated. Here, the crystal structure of the apo IF2 protein core from Thermus thermophilus has been determined by MAD phasing and the structures of GTP and GDP complexes were also obtained. The IF2-GTP complex was trapped by soaking with GTP in the cryoprotectant. The structures revealed conformational changes of the protein upon nucleotide binding, in particular in the P-loop region, which extend to the functionally relevant switch II region. The latter carries a catalytically important and conserved histidine residue which is observed in different conformations in the GTP and GDP complexes. Overall, this work provides the first crystal structure of a eubacterial IF2 and suggests that activation of GTP hydrolysis may occur by a conformational repositioning of the histidine residue.

PubMed: 23695237
DOI: 10.1107/S0907444913006422

実験手法

X-RAY DIFFRACTION (2.8 Å)