Figure 1.
Fig. 1. Redox-coupled conformational changes in the
His-503–Asp-91 region near the entrance of the D-pathway
deduced from the x-ray structures of bovine heart CcO from the
1.8-Å oxidized and 1.9-Å reduced x-ray structures of
bovine heart CcO. (a and b) The structures of the D-pathway
entrance regions in the reduced and oxidized states shown in
stereoviews. The red dotted lines indicate hydrogen bonds that
are independent of oxidation state. The blue dotted lines
indicate hydrogen bonds that are dependent on the oxidation
state. The blue, green, and orange sticks represent the C^ backbones of subunits
I, III, and VIIc, respectively. The red spheres represent fixed
water molecules. (c and d) Schematic representations of the
redox-coupled conformational changes of His-503 in the
Cd^2+-free and bound CcO, respectively. The blue and red
drawings represent the structures in the reduced and oxidized
states, respectively. The black dotted lines represent hydrogen
bonds uninfluenced by the oxidation state change. The blue and
red dotted lines depict hydrogen bonds appearing in the reduced
and oxidized states, respectively. The blue and red thick dotted
lines in d represent the coordination bonds that appear in the
reduced and oxidized states, respectively.
backbones of subunits
I, III, and VIIc, respectively. The red spheres represent fixed
water molecules. (c and d) Schematic representations of the
redox-coupled conformational changes of His-503 in the
Cd^2+-free and bound CcO, respectively. The blue and red
drawings represent the structures in the reduced and oxidized
states, respectively. The black dotted lines represent hydrogen
bonds uninfluenced by the oxidation state change. The blue and
red dotted lines depict hydrogen bonds appearing in the reduced
and oxidized states, respectively. The blue and red thick dotted
lines in d represent the coordination bonds that appear in the
reduced and oxidized states, respectively.