Fig. 6: Functional and structural divergence of Eg-CIV and cyt c.
From: Euglena’s atypical respiratory chain adapts to the discoidal cristae and flexible metabolism
Spectroscopic assays of cyt c reduction activities (a) and cyt c oxidation activities (b) of E. gracilis (green) and S. scrofa (orange) SC I + III2 + IV, monitored at 558 or 550 nm for Eg- or equine cyt c respectively as indicated. Data are presented as mean values ± standard error of mean (SEM), n = 3 biologically independent activity experiments. c Surface electrostatic potentials of Eg-CIV, equine cyt c (PDB 1HRC) and Eg-cyt c (UniProt: P00076, AlphaFold predicted structure). Electrostatic potentials are calculated using the APBS plugin of PyMOL colored by a symmetric color ramp from −5 kT/e (red) to +5 kT/e (blue). d Eg-CIV and Eg-cyt c aligned to the mammalian CIV-cyt c complex structure (PDB 5IY5). The star indicates electrostatic repulsion between Eg-CIV and Eg-cyt c if adopting the same association orientation as mammalian CIV-cyt c. Key residues are shown as sticks and colored by elements. e MD simulation (Run 1) of Eg-CIV+Eg-cyt c with potential key interacting residues shown as sticks and colored by elements. f MD trajectories (Run 1–3) of the center-of-mass distance between CIV and cyt c (upper panel) and the root-mean-square deviation (RMSD) of cyt c relative to the last frame of the simulation (lower panel) after aligning the entire CIV-cyt c complex with CIV during the 2000 ns MD simulation run. Source data are provided as a Source Data file.
