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

Pages

142-156

No. of pages

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)