Atomic structures of respiratory complex III < sub > 2 < /sub > , complex IV, and supercomplex III < sub > 2 < /sub > -IV from vascular plants

We present atomic models of CIII2, CIV, and SC III2+IV fromVigna 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 mitochondri al matrix. These structures challenge long-standing assumptions about the plant complexes and generate new mechanistic hypotheses.
Source: eLife - Category: Biomedical Science Tags: Plant Biology Structural Biology and Molecular Biophysics Source Type: research