Figure 3.

(A) Structural alignment of the nucleotide-free SufC monomer (light blue, PDB entry 2D3W) and one nucleotide-free SufC monomer from the SufC₂D₂ complex (green, chain C of PDB entry 2ZU0). C-Terminal helices 6 and 7 of SufD from SufC₂D₂ are shown at the top (blue). The Walker A, Walker B, and ABC signature motifs are colored yellow. The Q-loop is colored red (SufC monomer) or orange (SufC₂D₂). The D-loop is colored black (SufC monomer) or purple (SufC₂D₂). (B) Close-up view of panel A. Black dashed arrows indicate positional changes of those residues going from the structure of SufC alone to the SufC from SufC₂D₂. Gln85 (red to orange), Lys152 (yellow), and Glu171 (pink to cyan) are shown as sticks, and the Lys152–Glu171 salt bridge is shown as a red dashed line.