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Figure 5.
Figure 5. The seventh Ca^2+-binding site. (a) A stereo view
of electron density around the Ca-7 site of the mature form is
shown. The 2F[o]–F[c] map contoured at the 1.5σ and 5.0σ
levels are shown in blue and magenta, respectively. The calcium
ion and the water molecules are represented by cyan and red
spheres, respectively. The residues and water molecules that
coordinate with the calcium ion are labeled. (b) The structures
of the Ca-7 sites of the autoprocessed form (lime green), mature
form (orange), and unautoprocessed form 2 (gray) are
superimposed. The residues that coordinate with the calcium ion
are shown as a stick model.
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