1Y6I

Synechocystis GUN4

1Y6I の概要

• エントリーDOI: 10.2210/pdb1y6i/pdb
• 分子名称: Mg-chelatase cofactor GUN4 (2 entities in total)
• 機能のキーワード: helix-bundle, porphyrin binding, ligand binding protein
• 由来する生物種: Synechocystis sp.
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 26490.91

構造登録者

Verdecia, M.A.,Larkin, R.M.,Ferrer, J.L.,Riek, R.,Chory, J.,Noel, J.P. (登録日: 2004-12-06, 公開日: 2005-05-31, 最終更新日: 2024-02-14)

主引用文献

Verdecia, M.A.,Larkin, R.M.,Ferrer, J.L.,Riek, R.,Chory, J.,Noel, J.P.
Structure of the Mg-chelatase cofactor GUN4 reveals a novel hand-shaped fold for porphyrin binding
Plos Biol., 3:151-151, 2005

PubMed Abstract: In plants, the accumulation of the chlorophyll precursor Mg-protoporphyrin IX (Mg-Proto) in the plastid regulates the expression of a number of nuclear genes with functions related to photosynthesis. Analysis of the plastid-to-nucleus signaling activity of Mg-Proto in Arabidopsis thaliana led to the discovery of GUN4, a novel porphyrin-binding protein that also dramatically enhances the activity of Mg-chelatase, the enzyme that synthesizes Mg-Proto. GUN4 may also play a role in both photoprotection and the cellular shuttling of tetrapyrroles. Here we report a 1.78-A resolution crystal structure of Synechocystis GUN4, in which the porphyrin-binding domain adopts a unique three dimensional fold with a "cupped hand" shape. Biophysical and biochemical analyses revealed the specific site of interaction between GUN4 and Mg-Proto and the energetic determinants for the GUN4.Mg-Proto interaction. Our data support a novel protective function for GUN4 in tetrapyrrole trafficking. The combined structural and energetic analyses presented herein form the physical-chemical basis for understanding GUN4 biological activity, including its role in the stimulation of Mg-chelatase activity, as well as in Mg-Proto retrograde signaling.

PubMed: 15884974
DOI: 10.1371/journal.pbio.0030151

実験手法

X-RAY DIFFRACTION (1.78 Å)