Cryo-EM structure of the respiratory I + III 2 supercomplex from Arabidopsis thaliana at 2 Å resolution.

authored by
Niklas Klusch, Maximilian Dreimann, Jennifer Senkler, Nils Rugen, Werner Kühlbrandt, Hans-Peter Braun
Abstract

Protein complexes of the mitochondrial respiratory chain assemble into respiratory supercomplexes. Here we present the high-resolution electron cryo-microscopy structure of the Arabidopsis respiratory supercomplex consisting of complex I and a complex III dimer, with a total of 68 protein subunits and numerous bound cofactors. A complex I-ferredoxin, subunit B14.7 and P9, a newly defined subunit of plant complex I, mediate supercomplex formation. The component complexes stabilize one another, enabling new detailed insights into their structure. We describe (1) an interrupted aqueous passage for proton translocation in the membrane arm of complex I; (2) a new coenzyme A within the carbonic anhydrase module of plant complex I defining a second catalytic centre; and (3) the water structure at the proton exit pathway of complex III

2 with a co-purified ubiquinone in the Q

O site. We propose that the main role of the plant supercomplex is to stabilize its components in the membrane.

Organisation(s)
Institute of Plant Genetics
External Organisation(s)
Max Planck Institute of Biophysics
Type
Article
Journal
Nature plants
Volume
9
Pages
142-156
No. of pages
15
ISSN
2055-0278
Publication date
01.2023
Publication status
Published
Peer reviewed
Yes
Electronic version(s)
https://doi.org/10.1038/s41477-022-01308-6 (Access: Open)