1EJ7

CRYSTAL STRUCTURE OF UNACTIVATED TOBACCO RUBISCO WITH BOUND PHOSPHATE IONS

1EJ7 の概要

• エントリーDOI: 10.2210/pdb1ej7/pdb
• 関連するPDBエントリー: 8RUC
• 分子名称: RUBISCO (LARGE SUBUNIT), RUBISCO (SMALL SUBUNIT), PHOSPHATE ION, ... (4 entities in total)
• 機能のキーワード: tim barrel, alpha/beta barrel, lyase
• 由来する生物種: Nicotiana tabacum (common tobacco); 詳細
• 細胞内の位置: Plastid, chloroplast: P00876 P69249
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 67593.29

構造登録者

Duff, A.P.,Andrews, T.J.,Curmi, P.M.G. (登録日: 2000-03-01, 公開日: 2000-03-15, 最終更新日: 2024-11-13)

主引用文献

Duff, A.P.,Andrews, T.J.,Curmi, P.M.G.
The transition between the open and closed states of rubisco is triggered by the inter-phosphate distance of the bound bisphosphate.
J.Mol.Biol., 298:903-916, 2000

PubMed Abstract: d-Ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) catalyses the central CO(2)-fixing reaction of photosynthesis in a complex, multiple-step process. Several structures of rubisco complexed with substrate analogues, inhibitors and products have been determined by X-ray crystallography. The structures fall into two well-defined and distinct states. The active site is either "open" or "closed". The timing and mechanism of the transition between these two states have been uncertain. We solved the crystal structure of unactivated (metal-free) rubisco from tobacco with only inorganic phosphate bound and conclude that phosphate binding per se does not trigger closure, as it does in the similarly structured enzyme, triosephosphate isomerase. Comparison of all available rubisco structures suggests that, instead, the distance between the terminal phosphates (P1 and P2) of the bisphosphate ligand is the trigger: if that distance is less than 9.1 A, then the active site closes; if it is greater than 9.4 A then the enzyme remains open. Shortening of the inter-phosphate distance results from the ligand binding in a more curved conformation when O atoms of the ligand's sugar backbone interact either with the metal, if it is present, or with charged groups in the metal-binding site, if the metal is absent. This shortening brings the P1 phosphate into hydrogen bonding contact with Thr65. Thr65 exists in two discrete states related by a rotation of the backbone psi torsion angle. This rotation is coupled to domain rotation and hence to active site closure. Rotation of the side-chain of Thr65 also affects the C-terminal strand of large subunit which packs against Loop 6 after closure. The position of the C-terminal strand in the closed state is stabilised by multiple polar interactions with a distinctive highly-charged latch site involving the side-chain of Asp473. In the open state, this latch site may be occupied instead by phosphorylated anions.

PubMed: 10801357
DOI: 10.1006/jmbi.2000.3724

実験手法

X-RAY DIFFRACTION (2.45 Å)