Crystallization and preliminary crystallographic analysis of the Ras binding domain of RalGDS, a guanine nucleotide dissociation stimulator of the Ral protein

The RalGDS is a guanine nucleotide dissociation stimulator which activates the Ral protein, a Ras-like small GTPase. The C-terminal domain of the RalGDS (C-RalGDS) binds tightly to the effector loop of Ras suggesting that the RalGDS may be a crossing point of two signal tranduction pathways associated with the Ras and Ral proteins. C-RalGDS has been purified and crystallized in space group C2, with unit-cell dimensions a = 108.8, b = 30.7, c = 51.3 Å, β = 91.7° at 277 K and a = 103.8, b = 30.55, c = 51.4 Å, β = 94.9° for data collected at 100 K. The crystals diffract to 1.8 Å at a synchrotron radiation source. To use the multiple-wavelength anomalous diffraction method for phasing, a selenomethionine derivative of the protein has also been crystallized.