6LPI

Crystal Structure of AHAS holo-enzyme

6LPI の概要

• エントリーDOI: 10.2210/pdb6lpi/pdb
• 分子名称: Acetolactate synthase isozyme 1 small subunit, Acetolactate synthase isozyme 1 large subunit, FLAVIN-ADENINE DINUCLEOTIDE, ... (6 entities in total)
• 機能のキーワード: ahas, allosteric regulation, recombination
• 由来する生物種: Escherichia coli (strain K12); 詳細
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 301487.30

構造登録者

Zhang, Y.,Yang, X.,Xi, Z.,Shen, Y. (登録日: 2020-01-10, 公開日: 2020-11-18, 最終更新日: 2023-11-29)

主引用文献

Zhang, Y.,Li, Y.,Liu, X.,Sun, J.,Li, X.,Lin, J.,Yang, X.,Xi, Z.,Shen, Y.
Molecular architecture of the acetohydroxyacid synthase holoenzyme.
Biochem.J., 477:2439-2449, 2020

PubMed Abstract: The acetohydroxyacid synthase (AHAS) holoenzyme catalyzes the first step of branch-chain amino acid biosynthesis and is essential for plants and bacteria. It consists of a regulatory subunit (RSU) and a catalytic subunit (CSU). The allosteric mechanism of the AHAS holoenzyme has remained elusive for decades. Here, we determined the crystal structure of the AHAS holoenzyme, revealing the association between the RSU and CSU in an A2B2 mode. Structural analysis in combination with mutational studies demonstrated that the RSU dimer forms extensive interactions with the CSU dimer, in which a conserved salt bridge between R32 and D120 may act as a trigger to open the activation loop of the CSU, resulting in the activation of the CSU by the RSU. Our study reveals the activation mechanism of the AHAS holoenzyme.

PubMed: 32538427
DOI: 10.1042/BCJ20200292

実験手法

X-RAY DIFFRACTION (2.849 Å)