4O7G

Crystal Structure of Ascorbate-bound Cytochrome b561, crystal soaked in 1 M L-ascorbate for 40 minutes

4O7G の概要

• エントリーDOI: 10.2210/pdb4o7g/pdb
• 関連するPDBエントリー: 4O6Y 4O79
• 分子名称: Probable transmembrane ascorbate ferrireductase 2, PROTOPORPHYRIN IX CONTAINING FE, ASCORBIC ACID, ... (5 entities in total)
• 機能のキーワード: alpha helical transmembrane protein, ascorbate-dependent oxidoreductase, oxidoreductase
• 由来する生物種: Arabidopsis thaliana (thale-cress)
• 細胞内の位置: Membrane; Multi-pass membrane protein (Potential): Q9SWS1
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 53710.59

構造登録者

Lu, P.,Ma, D.,Yan, C.,Gong, X.,Du, M.,Shi, Y. (登録日: 2013-12-24, 公開日: 2014-02-05, 最終更新日: 2023-11-08)

主引用文献

Lu, P.,Ma, D.,Yan, C.,Gong, X.,Du, M.,Shi, Y.
Structure and mechanism of a eukaryotic transmembrane ascorbate-dependent oxidoreductase
Proc.Natl.Acad.Sci.USA, 111:1813-1818, 2014

PubMed Abstract: Vitamin C, also known as ascorbate, is required in numerous essential metabolic reactions in eukaryotes. The eukaryotic ascorbate-dependent oxidoreductase cytochrome b561 (Cyt b561), a family of highly conserved transmembrane enzymes, plays an important role in ascorbate recycling and iron absorption. Although Cyt b561 was identified four decades ago, its atomic structure and functional mechanism remain largely unknown. Here, we report the high-resolution crystal structures of cytochrome b561 from Arabidopsis thaliana in both substrate-free and substrate-bound states. Cyt b561 forms a homodimer, with each protomer consisting of six transmembrane helices and two heme groups. The negatively charged substrate ascorbate, or monodehydroascorbate, is enclosed in a positively charged pocket on either side of the membrane. Two highly conserved amino acids, Lys(81) and His(106), play an essential role in substrate recognition and catalysis. Our structural and biochemical analyses allow the proposition of a general electron transfer mechanism for members of the Cyt b561 family.

PubMed: 24449903
DOI: 10.1073/pnas.1323931111

実験手法

X-RAY DIFFRACTION (2.211 Å)