Expression, purification, and preliminary X-ray crystallographic analysis of the complex of G(alpha i3)-RGS5 from human with GDP/Mg2+/AlF4-

Abstract

Regulator of G-protein signaling 5 (RGS5), an inhibitor of Gq and Gi activation, is a member of the small RGS protein subfamily. However, despite significant process in the investigation of RGS5, no structure is yet available. In order to elucidate the mechanism of the RGS5 in G protein signaling pathway, we have overexpressed the RGS5 and G_i(3) from human in Escherichia coli and crystallized the complex of RGS5 and G alpha i(3) proteins with GDP/Mg2+/AlF4- at 3.0 angstrom resolution using a synchrotron radiation source. The complex crystals belong to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, with unit cell parameters a=b=95.9 angstrom, and c=138.8 angstrom. Assuming one complex protein in the crystallographic asymmetric unit, the calculated Matthews parameter (V-M) is 2.57 angstrom(3)/Da and solvent content is 52.2%.