Extended Data Fig. 5: Diversity of mitochondrial respiratory chain supercomplexes architecture in different organisms and the apicomplexan-conserved subunits and extensions that establish the divergent III2-IV interface in T. gondii.
From: Structure, assembly and inhibition of the Toxoplasma gondii respiratory chain supercomplex
(a) Overlay of supercomplex structures aligned on CIV highlights different architectures (luminal view), as revealed by differing positions of CIII from mammals (M. musculus, PDB 7o37 mature supercomplex), yeast (S. cerevisiae, PDB 6giq) and plant (V. radiata, 7jrp). The mammalian and T. gondii CIII homologs bind to opposite sides of CIV. (b) TgQCR6 (hinge protein) interaction with four contact sites on CIV highlighted. (c) T. gondii III2-IV interface (this study) of TgQCR6 with ApiCox10 involving contacts via an apicomplexan-conserved N-terminal extension. (d-e) Structural overlay (D) and structure-based multiple sequence alignment (E) of the murine, P. falciparum and T. gondii QCR6 homologs showing a conserved hairpin structure. The N-terminal QCR6 extension that interacts with ApiCox10 is also found in P. falciparum. The mammalian N-terminus is cleaved as part of a mitochondrial targeting sequence.
