ジャーナル: Sci Adv / 年: 2023 タイトル: High-resolution cryo-EM structures of plant cytochrome bf at work. 著者: Marcin Sarewicz / Mateusz Szwalec / Sebastian Pintscher / Paulina Indyka / Michał Rawski / Rafał Pietras / Bohun Mielecki / Łukasz Koziej / Marcin Jaciuk / Sebastian Glatt / Artur Osyczka / 要旨: Plants use solar energy to power cellular metabolism. The oxidation of plastoquinol and reduction of plastocyanin by cytochrome bf (Cyt bf) is known as one of the key steps of photosynthesis, but the ...Plants use solar energy to power cellular metabolism. The oxidation of plastoquinol and reduction of plastocyanin by cytochrome bf (Cyt bf) is known as one of the key steps of photosynthesis, but the catalytic mechanism in the plastoquinone oxidation site (Q) remains elusive. Here, we describe two high-resolution cryo-EM structures of the spinach Cyt bf homodimer with endogenous plastoquinones and in complex with plastocyanin. Three plastoquinones are visible and line up one after another head to tail near Q in both monomers, indicating the existence of a channel in each monomer. Therefore, quinones appear to flow through Cyt bf in one direction, transiently exposing the redox-active ring of quinone during catalysis. Our work proposes an unprecedented one-way traffic model that explains efficient quinol oxidation during photosynthesis and respiration.
詳細: Buffer and the diluted protein sample were filtered through a 0.22 um syringe filter. Prior to freezing, protein sample was concentrated on centrifugal filter units with 50K MWCO.
選択した数: 42951 詳細: given number of particles is after blob picker and 2D cleaning
CTF補正
ソフトウェア - 名称: cryoSPARC (ver. v3.3.1) ソフトウェア - 詳細: patch CTF, global and local CTF refinement 詳細: Non-uniform Refinement with iterative global CTF refinement and anisotropic magnification fitting タイプ: PHASE FLIPPING AND AMPLITUDE CORRECTION