RT Journal Article
SR Electronic
T1 Atomic structures of respiratory complex III<sub>2</sub>, complex IV and supercomplex III<sub>2</sub>-IV from vascular plants
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.08.30.274431
DO 10.1101/2020.08.30.274431
A1 María Maldonado
A1 Fei Guo
A1 James A. Letts
YR 2020
UL http://biorxiv.org/content/early/2020/08/31/2020.08.30.274431.abstract
AB 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 CIII2’s 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.