7E8N

Crystal structure of Type II citrate synthase (HyCS) from Hymenobacter sp. PAMC 26554

7E8N の概要

• エントリーDOI: 10.2210/pdb7e8n/pdb
• 分子名称: Citrate synthase, CITRIC ACID (3 entities in total)
• 機能のキーワード: citrate synthase, hymenobacter sp. pamc 26554, domain movement, ribosomal protein, transferase
• 由来する生物種: Hymenobacter sp. PAMC 26554
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 145653.32

構造登録者

Park, S.-H.,Lee, C.W.,Bae, D.-W.,Lee, J.H. (登録日: 2021-03-02, 公開日: 2022-01-12, 最終更新日: 2025-09-17)

主引用文献

Park, S.H.,Lee, C.W.,Bae, D.W.,Do, H.,Jeong, C.S.,Hwang, J.,Cha, S.S.,Lee, J.H.
Structural basis of the cooperative activation of type II citrate synthase (HyCS) from Hymenobacter sp. PAMC 26554.
Int.J.Biol.Macromol., 183:213-221, 2021

PubMed Abstract: Citrate synthase (CS) catalyzes the formation of citrate and coenzyme A from acetyl-CoA and oxaloacetate. CS exists in two forms: type I and type II. We determined the citrate-bound crystal structure of type II CS from the Hymenobacter sp. PAMC 26554 bacterium (HyCS; isolated from Antarctic lichen). Citrate molecules bound to a cleft between the large and small domains of HyCS. Structural comparison of HyCS with other type II CSs revealed that type II CSs have a highly conserved flexible hinge region (residues G264-P265 in HyCS), enabling correct positioning of active site residues. Notably, the catalytic His266 residue of HyCS interacted with Trp262 in the inactive (unliganded open) state of other type II CSs, whereas the His266 residue moved to the active site via a small-domain swing motion, interacting with the bound citrate in the closed conformation of HyCS. However, type I CSs lack this tryptophan residue and face-to-edge interactions. Thus, type II CSs might have a unique domain-motion control mechanism enabling a tight allosteric regulation. An activity assay using a W262A mutant showed a Hill coefficient of 2.4; thus, the interaction between Trp262 and His266 was closely related to the positive cooperative ligand binding of type II CS.

PubMed: 33910038
DOI: 10.1016/j.ijbiomac.2021.04.141

実験手法

X-RAY DIFFRACTION (2.2 Å)