Structure of the Drosophila melanogaster Rab6 GTPase at 1.4 Å resolution

The crystal structure of Drosphila melanogaster Rab6 bound to the non-hydrolysable GTP analogue GMPPNP has been determined at a resolution of 1.4 Å. Rab6 is a small GTPase that belongs to the p21 Ras superfamily. It is involved in vesicle trafficking between the Golgi apparatus and endosomes/ER in eukaryotes. The GDP-bound inactive protein undergoes conformational changes when the nucleotide is exchanged to GTP, allowing Rab6 to interact with a variety of different effector proteins. To further understand how these changes affect downstream protein binding, the crystal structure of Rab6 from Drosophila melanogaster has been solved to 1.4 Å resolution, the highest resolution for a Rab6 structure to date. The crystals belonged to space group C2, with unit-cell parameters a = 116.5, b = 42.71, c = 86.86 Å, α = 90, β = 133.12, γ = 90°. The model was refined to an R factor of 14.5% and an R_free of 17.3%