Purification, crystallization and preliminary X-ray diffraction analysis of an archaeal ABC-ATPase

In the archaeon Sulfolobus solfataricus glucose uptake is mediated by an ABC transport system. The ABC-ATPase of this transporter (GlcV) has been overproduced in Escherichia coli and purified. Crystals of GlcV suitable for data collection were obtained in the absence of nucleotide by microseeding combined with vapour diffusion from a mixture of PEG polymers and NaCl. Appearing under identical conditions, two crystal forms have been characterized by X-ray diffraction. Both forms diffract to high resolution using synchrotron radiation and both belong to space group P2₁2₁2₁. The related crystal forms A (unit-cell parameters a = 47.0, b = 48.2, c = 182.1 Å) and B (a = 47.0, b = 146.6, c = 178.5 Å) feature one and three GlcV molecules in the asymmetric unit, respectively, with a solvent content of about 50%. Crystals have also been obtained in the presence of sodium iodide. From single-wavelength anomalous diffraction data extending to 2.1 Å resolution, an iodide substructure could be resolved.