2C2B

Crystallographic structure of Arabidopsis thaliana Threonine synthase complexed with pyridoxal phosphate and S-adenosylmethionine

2C2B の概要

• エントリーDOI: 10.2210/pdb2c2b/pdb
• 分子名称: THREONINE SYNTHASE 1, CHLOROPLASTIC, S-ADENOSYLMETHIONINE, 2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL, ... (5 entities in total)
• 機能のキーワード: threonine synthesis, allostery, synthase, lyase
• 由来する生物種: ARABIDOPSIS THALIANA (MOUSE-EAR CRESS)
• 細胞内の位置: Plastid, chloroplast: Q9S7B5
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 326944.07

構造登録者

Mas-Droux, C.,Biou, V.,Dumas, R. (登録日: 2005-09-27, 公開日: 2005-11-28, 最終更新日: 2023-12-13)

主引用文献

Mas-Droux, C.,Biou, V.,Dumas, R.
Allosteric Threonine Synthase: Reorganization of the Pyridoxal Phosphate Site Upon Asymmetric Activation Through S-Adenosylmethionine Binding to a Novel Site.
J.Biol.Chem., 281:5188-, 2006

PubMed Abstract: Threonine synthase (TS) is a fold-type II pyridoxal phosphate (PLP)-dependent enzyme that catalyzes the ultimate step of threonine synthesis in plants and microorganisms. Unlike the enzyme from microorganisms, plant TS is activated by S-adenosylmethionine (AdoMet). The mechanism of activation has remained unknown up to now. We report here the crystallographic structures of Arabidopsis thaliana TS in complex with PLP (aTS) and with PLP and AdoMet (aTS-AdoMet), which show with atomic detail how AdoMet activates TS. The aTS structure reveals a PLP orientation never previously observed for a type II PLP-dependent enzyme and explains the low activity of plant TS in the absence of its allosteric activator. The aTS-AdoMet structure shows that activation of the enzyme upon AdoMet binding triggers a large reorganization of active site loops in one monomer of the structural dimer and allows the displacement of PLP to its active conformation. Comparison with other TS structures shows that activation of the second monomer may be triggered by substrate binding. This structure also discloses a novel fold for two AdoMet binding sites located at the dimer interface, each site containing two AdoMet effectors bound in tandem. Moreover, aTS-AdoMet is the first structure of an enzyme that uses AdoMet as an allosteric effector.

PubMed: 16319072
DOI: 10.1074/JBC.M509798200

実験手法

X-RAY DIFFRACTION (2.6 Å)