Figure 6.
FIGURE 6. Residual difference electron densities (contoured
at 3 ) in the pore region.
Weighted difference density maps using (mFobs-DFcalc) terms as
defined in Refmac (25) were used. Only the density peaks within
a generous box (7 x 10 x 22 Å) covering the central pore
region are displayed. Selected side chains at the periplasmic
pore entry and along the pore are shown as ball-and-stick
models. Positions corresponding to sites Am1-Am4 (7) are shown
in black (S1-S4). A, difference densities from two native
crystals in blue and red (buffer containing imidazole). B,
difference densities and the side chains of residues 168 and 318
for the H168F and H318F in blue and red, respectively. C,
difference densities and the refined side chains of residues 168
and 318 for H168A and H168E in blue and red, respectively.
Except for H168A, all mutant crystals contain imidazole. The S4
peak position observed here is always about 1 Å closer to
the cytoplasmic side than the Am4 site.
The above figure is reprinted
by permission from the ASBMB:
J Biol Chem
(2006,
281,
39492-39498)
copyright 2006.
) in the pore region.
Weighted difference density maps using (mFobs-DFcalc) terms as
defined in Refmac (25) were used. Only the density peaks within
a generous box (7 x 10 x 22 Å) covering the central pore
region are displayed. Selected side chains at the periplasmic
pore entry and along the pore are shown as ball-and-stick
models. Positions corresponding to sites Am1-Am4 (7) are shown
in black (S1-S4). A, difference densities from two native
crystals in blue and red (buffer containing imidazole). B,
difference densities and the side chains of residues 168 and 318
for the H168F and H318F in blue and red, respectively. C,
difference densities and the refined side chains of residues 168
and 318 for H168A and H168E in blue and red, respectively.
Except for H168A, all mutant crystals contain imidazole. The S4
peak position observed here is always about 1 Å closer to
the cytoplasmic side than the Am4 site.