3BB4

Crystal structure of Toc33 from Arabidopsis thaliana in complex with Mg2+ and GMPPNP

3BB4 の概要

• エントリーDOI: 10.2210/pdb3bb4/pdb
• 関連するPDBエントリー: 3BB1 3BB3
• 分子名称: T7I23.11 protein, MAGNESIUM ION, PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER, ... (4 entities in total)
• 機能のキーワード: rossmann fold, gtpase domain, chloroplast import, hydrolase
• 由来する生物種: Arabidopsis thaliana (thale cress)
• 細胞内の位置: Plastid, chloroplast outer membrane ; Single- pass membrane protein : O23680
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 29804.02

構造登録者

Koenig, P.,Sinning, I.,Schleiff, E.,Tews, I. (登録日: 2007-11-09, 公開日: 2008-04-01, 最終更新日: 2023-11-01)

主引用文献

Koenig, P.,Oreb, M.,Hofle, A.,Kaltofen, S.,Rippe, K.,Sinning, I.,Schleiff, E.,Tews, I.
The GTPase cycle of the chloroplast import receptors Toc33/Toc34: implications from monomeric and dimeric structures.
Structure, 16:585-596, 2008

PubMed Abstract: Transport of precursor proteins across chloroplast membranes involves the GTPases Toc33/34 and Toc159 at the outer chloroplast envelope. The small GTPase Toc33/34 can homodimerize, but the regulation of this interaction has remained elusive. We show that dimerization is independent of nucleotide loading state, based on crystal structures of dimeric Pisum sativum Toc34 and monomeric Arabidopsis thaliana Toc33. An arginine residue is--in the dimer--positioned to resemble a GAP arginine finger. However, GTPase activation by dimerization is sparse and active site features do not explain catalysis, suggesting that the homodimer requires an additional factor as coGAP. Access to the catalytic center and an unusual switch I movement in the dimeric structure support this finding. Potential binding sites for interactions within the Toc translocon or with precursor proteins can be derived from the structures.

PubMed: 18400179
DOI: 10.1016/j.str.2008.01.008

実験手法

X-RAY DIFFRACTION (2.85 Å)