Figure 1.
FIGURE 1. Crystallographic analysis of amylomaltase
complexes. A, stereo figure of the F[o] - DF[c] electron density
for acarbose bound to Asp-293, calculated prior to incorporation
of acarbose in the model. The density was contoured at 2.5 and
overlaid on the refined structure. B, F[o] - DF[c] electron
density after refinement with a non-covalently bound acarbose.
To check the density for the covalent bond and to correctly
identify the various acarbose residues, the Asp-293 carboxylate
group as well as the acarbose 6-OH groups were omitted from the
calculations (see "Materials and Methods"). Positive difference
density is shown in green (3.5 ), negative density in
red (-3.5 ). 2mF[o] - DF[c]
density (blue, 1.0 ) (C) F[o] - DF[c]
electron density (green, 2.5 ) (D) for the covalent
intermediate-4-deoxyglucose complex. To avoid model bias, both
maps were calculated prior to the incorporation of
4-deoxyglucose in the model. All figures were produced using
PyMol (37).
The above figure is reprinted
by permission from the ASBMB:
J Biol Chem
(2007,
282,
17242-17249)
copyright 2007.
and
overlaid on the refined structure. B, F[o] - DF[c] electron
density after refinement with a non-covalently bound acarbose.
To check the density for the covalent bond and to correctly
identify the various acarbose residues, the Asp-293 carboxylate
group as well as the acarbose 6-OH groups were omitted from the
calculations (see "Materials and Methods"). Positive difference
density is shown in green (3.5