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Figure 3.
Figure 3. GTPase Active Site in the
PRG-rgRGS:Gα13•GDP•AlF[4]^− Complex
(A) Electron
density (cages) at the active site from a 2.25 Å
σ[A]−weighted 2F[o]−F[c] difference map (Read, 1986) is
contoured at 1.6 standard deviations above the mean. Only
densities of the PRG-rgRGS N terminus, GDP•Mg^2+•AlF[4]^−
and the axial water molecule bound to AlF[4]^− are shown.
Hydrogen bonds are drawn as dotted lines.
(B) Structural
comparison of active sites from
PRG-rgRGS:Gα13•GDP•AlF[4]^− complex and
p115-rgRGS:Gα13/i1•GDP•AlF[4]^− complex. Elements from
Gα13/i1 are colored gray and the N terminus of p115-rgRGS is
colored brown.
(C) Stimulation of GTPase activity of Gα13
by increasing concentrations of wild-type and mutated PRG-rgRGS.
Amino acids mutated in PRG-rgRGS are colored red.
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