6HUM

Structure of the photosynthetic complex I from Thermosynechococcus elongatus

Summary for 6HUM

• Entry DOI: 10.2210/pdb6hum/pdb
• EMDB information: 0281
• Descriptor: NAD(P)H-quinone oxidoreductase subunit 1, NAD(P)H-quinone oxidoreductase subunit I, NAD(P)H-quinone oxidoreductase subunit K, ... (21 entities in total)
• Functional Keywords: respiratory complex, ferredoxin, cyclic electron flow, complex i, membrane protein complex, proton transport
• Biological source: Thermosynechococcus elongatus BP-1; More
• Total number of polymer chains: 18
• Total formula weight: 455560.25

Authors

Schuller, J.M.,Schuller, S.K.,Kurisu, G.,Engel, B.D.,Nowaczyk, M.M. (deposition date: 2018-10-09, release date: 2019-01-09, Last modification date: 2024-05-15)

Primary citation

Schuller, J.M.,Birrell, J.A.,Tanaka, H.,Konuma, T.,Wulfhorst, H.,Cox, N.,Schuller, S.K.,Thiemann, J.,Lubitz, W.,Setif, P.,Ikegami, T.,Engel, B.D.,Kurisu, G.,Nowaczyk, M.M.
Structural adaptations of photosynthetic complex I enable ferredoxin-dependent electron transfer.
Science, 363:257-260, 2019

PubMed Abstract: Photosynthetic complex I enables cyclic electron flow around photosystem I, a regulatory mechanism for photosynthetic energy conversion. We report a 3.3-angstrom-resolution cryo-electron microscopy structure of photosynthetic complex I from the cyanobacterium The model reveals structural adaptations that facilitate binding and electron transfer from the photosynthetic electron carrier ferredoxin. By mimicking cyclic electron flow with isolated components in vitro, we demonstrate that ferredoxin directly mediates electron transfer between photosystem I and complex I, instead of using intermediates such as NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). A large rate constant for association of ferredoxin to complex I indicates efficient recognition, with the protein subunit NdhS being the key component in this process.

PubMed: 30573545
DOI: 10.1126/science.aau3613

Experimental method

ELECTRON MICROSCOPY (3.34 Å)