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Figure 2.
Figure 2. EZ-MBP-HA remains open in solution when bound to
Zn2+. The experimental SAXS curves for Zn2+-free and Zn2+-bound
EZ-MBP-HA were compared to the crystal structures of open and
closed forms of wild-type MBP. All scattering curves are
represented as a plot of the momentum transfer, Q (a function of
the scattering angle), versus the natural logarithm of the
scattering intensity. In each case, differences between the
scattering intensities in the two experiments are plotted as a
percentage of the total signal. (a) Experimental SAXS curves for
wild-type MBP in the closed ligand-bound form (red) and the open
ligand-free form (black) were overlaid, illustrating the
expected SAXS changes when the protein undergoes conformational
change from open to closed. (b) A superposition of SAXS curves
from Zn2+-free (black) and Zn2+-bound EZ-MBP-HA (red) shows that
there is little, if any, conformational change in response to
Zn2+ binding. To find whether EZ-MBP-HA exists in an open or
closed conformation in solution, experimental SAXS data from
Zn2+-bound MBP (black) were compared with theoretical scattering
from (c) closed MBP and (d) open MBP, both shown in red.
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