Figure 3.
Fig. 3. ADP binding. (A) Stereoview of the electron density
(2 contour level) of one
of the bound ADP-Mg2+ obtained from a simulated annealing F[o] -
F[c] map, with ADP-Mg2+ molecules omitted in the structure
factor calculation. The ADP-Mg2+ is represented in
ball-and-stick model. Water molecules are colored in pink. To
illustrate that there is no density in the expected position of
the phosphate, the ATP
molecule also is shown in gray. The ATP model was obtained by
aligning the Walker A motif of the ATP-bound form (12) with that
of the ADP-bound form. (B) Atomic details of the interaction
between MalK and ADP-Mg2+. Residues contacting the ADP and
magnesium ion are labeled. Hydrogen-bonding and salt-bridge
interactions are marked by dashed lines in orange and blue,
respectively. Color identification for the residues is as
follows: O atoms, red; N atoms, blue; C atoms, gray; and P and S
atoms, orange.
contour level) of one
of the bound ADP-Mg2+ obtained from a simulated annealing F[o] -
F[c] map, with ADP-Mg2+ molecules omitted in the structure
factor calculation. The ADP-Mg2+ is represented in
ball-and-stick model. Water molecules are colored in pink. To
illustrate that there is no density in the expected position of
the 
phosphate, the ATP
molecule also is shown in gray. The ATP model was obtained by
aligning the Walker A motif of the ATP-bound form (12) with that
of the ADP-bound form. (B) Atomic details of the interaction
between MalK and ADP-Mg2+. Residues contacting the ADP and
magnesium ion are labeled. Hydrogen-bonding and salt-bridge
interactions are marked by dashed lines in orange and blue,
respectively. Color identification for the residues is as
follows: O atoms, red; N atoms, blue; C atoms, gray; and P and S
atoms, orange.