Crystallization and preliminary X-ray analysis of the periplasmic receptor (PotF) of the putrescine transport system in Escherichia coli

The primary receptor (PotF) of the putrescine transport system in E.coli has been crystallized by the hanging-drop vapor-diffusion technique. The crystals belong to the space group P2(1)2(1)2 with unit-cell dimensions a = 269.4, b = 82.33 and c = 93.74 Angstrom. The crystals diffract beyond 2.2 Angstrom with a rotating-anode X-ray source. A complete data set from the native crystals has been collected and processed at 2.3 Angstrom resolution. Two heavy-atom derivatives have been prepared from the same Pt compound at 293 and 277 K. The difference Patterson maps revealed completely different major heavy-atom sites between these two derivatives.