7ZYV

Cryo-EM structure of catalytically active Spinacia oleracea cytochrome b6f in complex with endogenous plastoquinones at 2.13 A resolution

Summary for 7ZYV

• Entry DOI: 10.2210/pdb7zyv/pdb
• EMDB information: 14123 15027
• Descriptor: Cytochrome b6, PROTOPORPHYRIN IX CONTAINING FE, HEME C, ... (17 entities in total)
• Functional Keywords: cytochrome, spinacia oleracea, plastoquinones, cryo-em, photosynthesis
• Biological source: Spinacia oleracea (spinach); More
• Total number of polymer chains: 18
• Total formula weight: 290610.70

Authors

Sarewicz, M.,Szwalec, M.,Pintscher, S.,Indyka, P.,Rawski, M.,Pietras, R.,Mielecki, B.,Koziej, L.,Jaciuk, M.,Glatt, S.,Osyczka, A. (deposition date: 2022-05-25, release date: 2023-01-25)

Primary citation

Sarewicz, M.,Szwalec, M.,Pintscher, S.,Indyka, P.,Rawski, M.,Pietras, R.,Mielecki, B.,Koziej, L.,Jaciuk, M.,Glatt, S.,Osyczka, A.
High-resolution cryo-EM structures of plant cytochrome b 6 f at work.
Sci Adv, 9:eadd9688-eadd9688, 2023

PubMed Abstract: 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.

PubMed: 36638176
DOI: 10.1126/sciadv.add9688

Experimental method

ELECTRON MICROSCOPY (2.13 Å)