7E2R

The ligand-free structure of Arabidopsis thaliana GUN4

7E2R の概要

• エントリーDOI: 10.2210/pdb7e2r/pdb
• 分子名称: Tetrapyrrole-binding protein, chloroplastic (2 entities in total)
• 機能のキーワード: gun4, ligand binding protein, signaling protein
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 47251.11

構造登録者

Liu, L.,Hu, J. (登録日: 2021-02-07, 公開日: 2021-08-25, 最終更新日: 2023-11-29)

主引用文献

Hu, J.H.,Chang, J.W.,Xu, T.,Wang, J.,Wang, X.,Lin, R.,Duanmu, D.,Liu, L.
Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4.
Protein Sci., 30:2083-2091, 2021

PubMed Abstract: The chlorophyll biosynthesis regulator GENOMES UNCOUPLED 4 (GUN4) is conserved in nearly all oxygenic photosynthetic organisms. Recently, GUN4 has been found to be able to bind the linear tetrapyrroles (bilins) and stimulate the magnesium chelatase activity in the unicellular green alga Chlamydomonas reinhardtii. Here, we characterize GUN4 proteins from Arabidopsis thaliana and the cyanobacterium Synechocystis sp. PCC 6803 for their ability to bind bilins, and present the crystal structures of Synechocystis GUN4 in biliverdin-bound, phycocyanobilin-bound, and phytochromobilin-bound forms at the resolutions of 1.05, 1.10, and 1.70 Å, respectively. These linear molecules adopt a cyclic-helical conformation, and bind more tightly than planar porphyrins to the tetrapyrrole-binding pocket of GUN4. Based on structural comparison, we propose a working model of GUN4 in regulation of tetrapyrrole biosynthetic pathway, and address the role of the bilin-bound GUN4 in retrograde signaling.

PubMed: 34382282
DOI: 10.1002/pro.4164

実験手法

X-RAY DIFFRACTION (2.3 Å)