Figure 2.
FIGURE 2. The G85R mutation site and the copper- and
zinc-binding sites. The wild type protein is shown in yellow. A,
three of the four conformations observed in the 10 unique
subunits of the four crystal structures are shown in light blue,
green, and pink, respectively (see text). Copper and zinc ions
are represented as cyan and gray spheres, respectively. The dual
hydrogen bonds formed by Asp^124 to the copper ligand His^46 and
the zinc ligand His^71 as well as the hydrogen bonding network
between Pro^74, Arg^79, and Asp^101 are shown as dotted lines.
B, the image is the same as in A except rotated 90°
around the horizontal and vertical axes in the plane of the
page. The electrostatic loop has been removed for clarity. C,
the location of the three proline residues of the zinc loop (see
text). The disulfide loop (residues 50-62), a substructure of
the zinc loop, is shown in green. The remainder of the zinc loop
containing the zinc-binding ligands, residues 63-83, is shown in
blue. Pro^62, Pro^66, and Pro^74 in the zinc-bound conformation
of the zinc loop are shown in magenta. The altered position of
the five-membered ring of Pro^74 and the Arg^85 side chain are
shown in orange. The hydrogen bond normally found between the
carbonyl oxygen of Pro^74 and the guanidinium group of Arg^79 is
disrupted. D, structural state four (see text) found in G85R
subunits C, E, and F (see Table 2). The absence of electron
density around the carbon and the Arg^85
side chain indicates that this residue is conformationally
mobile, sampling many positions. This movement is correlated
with both zinc deficiency in the zinc site and disorder of the
zinc and electrostatic loop elements.
90°
around the horizontal and vertical axes in the plane of the
page. The electrostatic loop has been removed for clarity. C,
the location of the three proline residues of the zinc loop (see
text). The disulfide loop (residues 50-62), a substructure of
the zinc loop, is shown in green. The remainder of the zinc loop
containing the zinc-binding ligands, residues 63-83, is shown in
blue. Pro^62, Pro^66, and Pro^74 in the zinc-bound conformation
of the zinc loop are shown in magenta. The altered position of
the five-membered ring of Pro^74 and the Arg^85 side chain are
shown in orange. The hydrogen bond normally found between the
carbonyl oxygen of Pro^74 and the guanidinium group of Arg^79 is
disrupted. D, structural state four (see text) found in G85R
subunits C, E, and F (see Table 2). The absence of electron
density around the 
carbon and the Arg^85
side chain indicates that this residue is conformationally
mobile, sampling many positions. This movement is correlated
with both zinc deficiency in the zinc site and disorder of the
zinc and electrostatic loop elements.