4ZHJ

Crystal Structure of the Catalytic Subunit of Magnesium Chelatase

4ZHJ の概要

• エントリーDOI: 10.2210/pdb4zhj/pdb
• 分子名称: Mg-chelatase subunit ChlH (2 entities in total)
• 機能のキーワード: mg-chelatase, gun5, metal binding protein
• 由来する生物種: Synechocystis sp. PCC 6803 substr. Kazusa
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 301743.00

構造登録者

Chen, X.,Pu, H.,Fang, Y.,Liu, L. (登録日: 2015-04-25, 公開日: 2015-08-26, 最終更新日: 2024-03-20)

主引用文献

Chen, X.,Pu, H.,Fang, Y.,Wang, X.,Zhao, S.,Lin, Y.,Zhang, M.,Dai, H.E.,Gong, W.,Liu, L.
Crystal structure of the catalytic subunit of magnesium chelatase
Nat.Plants, 1:15125-15125, 2015

PubMed Abstract: Tetrapyrroles, including haem and chlorophyll, play vital roles for various biological processes, such as respiration and photosynthesis, and their biosynthesis is critical for virtually all organisms. In photosynthetic organisms, magnesium chelatase (MgCh) catalyses insertion of magnesium into the centre of protoporphyrin IX, the branch-point precursor for both haem and chlorophyll, leading tetrapyrrole biosynthesis into the magnesium branch(1,2). This reaction needs a cooperated action of the three subunits of MgCh: the catalytic subunit ChlH and two AAA(+) subunits, ChlI and ChlD (refs 3-5). To date, the mechanism of MgCh awaits further elucidation due to a lack of high-resolution structures, especially for the ∼150 kDa catalytic subunit. Here we report the crystal structure of ChlH from the photosynthetic cyanobacterium Synechocystis PCC 6803, solved at 2.5 Å resolution. The active site is buried deeply inside the protein interior, and the surrounding residues are conserved throughout evolution. This structure helps to explain the loss of function reported for the cch and gun5 mutations of the ChlH subunit, and to provide the molecular basis of substrate channelling during the magnesium-chelating process. The structure advances our understanding of the holoenzyme of MgCh, a metal chelating enzyme other than ferrochelatase.

PubMed: 27250678
DOI: 10.1038/nplants.2015.125

実験手法

X-RAY DIFFRACTION (2.502 Å)