Fig. 5.

The IscS-IscU-CyaY complex. (A) IscS-IscU-CyaY complex structure, where two CyaY proteins (blue) are bound in the cleft formed between IscS dimer (orange) and IscU (pink). (B) Electrostatic potential surfaces for the IscS-IscU complex (right) and CyaY (left). Structure orientation is chosen to better visualize the mutual interacting surfaces on both systems. (C) Steric clashes between CyaY and [Fe—S]-loaded IscU (purple) in a hypothetical ternary complex structure built from the superposition of A. fulgidus IscU onto the average ternary structure (with IscU omitted) from our simulation superposed on the IscS dimer only. (D) Zoomed view of the interface between the IscS dimer and CyaY. The more persistent intermolecular salt bridges (see Table S1) are depicted as sticks connecting Cα atoms (spheres) belonging to the corresponding charged residues.