4N7R

Crystal structure of Arabidopsis glutamyl-tRNA reductase in complex with its binding protein

4N7R の概要

• エントリーDOI: 10.2210/pdb4n7r/pdb
• 分子名称: Glutamyl-tRNA reductase 1, chloroplastic, Genomic DNA, chromosome 3, P1 clone: MXL8 (3 entities in total)
• 機能のキーワード: nadp-binding glutamyl-trna reductase, reductase, nadph, trna-glu, chloroplast, oxidoreductase-protein binding complex, oxidoreductase/protein binding
• 由来する生物種: Arabidopsis thaliana (mouse-ear cress); 詳細
• 細胞内の位置: Plastid, chloroplast membrane: P42804
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 172825.10

構造登録者

Zhao, A.,Fang, Y.,Lin, Y.,Gong, W.,Liu, L. (登録日: 2013-10-16, 公開日: 2014-05-14, 最終更新日: 2024-03-20)

主引用文献

Zhao, A.,Fang, Y.,Chen, X.,Zhao, S.,Dong, W.,Lin, Y.,Gong, W.,Liu, L.
Crystal structure of Arabidopsis glutamyl-tRNA reductase in complex with its stimulator protein
Proc.Natl.Acad.Sci.USA, 111:6630-6635, 2014

PubMed Abstract: Tetrapyrrole biosynthesis in plants, algae, and most bacteria starts from the NADPH-dependent reduction of glutamyl-tRNA by glutamyl-tRNA reductase (GluTR). The GluTR-catalyzed reaction is the rate-limiting step, and GluTR is the target of multiple posttranslational regulations, such as heme feedback inhibition, for the tetrapyrrole biosynthetic pathway. A recently identified GluTR regulator, GluTR binding protein (GluBP), has been shown to spatially organize tetrapyrrole synthesis by distributing GluTR into different suborganellar locations. Here we report the complex structure of GluTR-GluBP from Arabidopsis thaliana. The dimeric GluBP binds symmetrically to the catalytic domains of the V-shaped GluTR dimer via its C-terminal domain. A substantial conformational change of the GluTR NADPH-binding domain is observed, confirming the postulated rotation of the NADPH-binding domain for hydride transfer from NADPH to the substrate. Arg146, "guarding the door" for metabolic channeling, adopts alternative conformations, which may represent steps involved in substrate recognition and product release. A coupled enzyme assay shows that GluBP stimulates GluTR catalytic efficiency with an approximate threefold increase of the 5-aminolevulinic acid formation rate. In addition, the GluTR activity can be inhibited by heme in a concentration-dependent way regardless of the presence of GluBP. A structural alignment indicates that GluBP belongs to a heme-binding family involved in heme metabolism. We propose a catalytic mechanism model for GluTR, through which photosynthetic organisms can achieve precise regulation of tetrapyrrole biosynthesis.

PubMed: 24753615
DOI: 10.1073/pnas.1400166111

実験手法

X-RAY DIFFRACTION (2.802 Å)