7JK9

Helical filaments of plant light-dependent protochlorophyllide oxidoreductase (LPOR) bound to NADPH, Pchlide, and membrane

これはPDB形式変換不可エントリーです。

7JK9 の概要

• エントリーDOI: 10.2210/pdb7jk9/pdb
• EMDBエントリー: 22364
• 分子名称: Protochlorophyllide reductase B, chloroplastic, NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, Protochlorophyllide, ... (4 entities in total)
• 機能のキーワード: reductase, light-activated, ligand-protein complex, photosynthesis
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• タンパク質・核酸の鎖数: 40
• 化学式量合計: 1822429.40

構造登録者

Nguyen, H.C.,Gabruk, M.,Frost, A. (登録日: 2020-07-28, 公開日: 2021-03-17, 最終更新日: 2024-05-15)

主引用文献

Nguyen, H.C.,Melo, A.A.,Kruk, J.,Frost, A.,Gabruk, M.
Photocatalytic LPOR forms helical lattices that shape membranes for chlorophyll synthesis.
Nat.Plants, 7:437-444, 2021

PubMed Abstract: Chlorophyll biosynthesis, crucial to life on Earth, is tightly regulated because its precursors are phototoxic. In flowering plants, the enzyme light-dependent protochlorophyllide oxidoreductase (LPOR) captures photons to catalyse the penultimate reaction: the reduction of a double bond within protochlorophyllide (Pchlide) to generate chlorophyllide (Chlide). In darkness, LPOR oligomerizes to facilitate photon energy transfer and catalysis. However, the complete three-dimensional structure of LPOR, the higher-order architecture of LPOR oligomers and the implications of these self-assembled states for catalysis, including how LPOR positions Pchlide and the co-factor NADPH, remain unknown. Here, we report the atomic structure of LPOR assemblies by electron cryo-microscopy. LPOR polymerizes with its substrates into helical filaments around constricted lipid bilayer tubes. Portions of LPOR and Pchlide insert into the outer membrane leaflet, targeting the product, Chlide, to the membrane for the final reaction site of chlorophyll biosynthesis. In addition to its crucial photocatalytic role, we show that in darkness LPOR filaments directly shape membranes into high-curvature tubules with the spectral properties of the prolamellar body, whose light-triggered disassembly provides lipids for thylakoid assembly. Moreover, our structure of the catalytic site challenges previously proposed reaction mechanisms. Together, our results reveal a new and unexpected synergy between photosynthetic membrane biogenesis and chlorophyll synthesis in plants, orchestrated by LPOR.

PubMed: 33875834
DOI: 10.1038/s41477-021-00885-2

実験手法

ELECTRON MICROSCOPY (3.1 Å)