Atomic structures of respiratory complex III2 complex IV and supercomplex III2-IV from vascular plants

ABSTRACT: Mitochondrial complex III (CIII2) and complex IV (CIV) which can associate into a higher-order supercomplex (SC III2 IV) play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII2, CIV and SC III2 IV from Vigna radiata determined by single-particle cryoEM. The structures reveal plant-specific differences in the MPP domain of CIII2 and define the subunit composition of CIV. Conformational heterogeneity analysis of CIII2 revealed long-range, coordinated movements across the complex as well as the motion of CIII2s iron-sulfur head domain. The CIV structure suggests that, in plants, proton translocation does not occur via the H-channel. The supercomplex interface differs significantly from that in yeast and bacteria in its interacting subunits angle of approach and limited interactions in the mitochondrial matrix. These structures challenge long-standing assumptions about the plant complexes, generate new mechanistic hypotheses and allow for the generation of more selective agricultural inhibitors.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Vigna Radiata (ncbitaxon:157791)

SUBMITTER: James A. Letts  

PROVIDER: MSV000086237 | MassIVE | Mon Oct 05 15:18:00 BST 2020

SECONDARY ACCESSION(S): PXD021850

REPOSITORIES: MassIVE