Crystallization and preliminary X-ray analysis of the controller protein C.AhdI from Aeromonas hydrophilia

Single crystals of purified homodimeric controller protein from Aeromonas hydrophilia (C.AhdI) have been grown under several different conditions using vapour diffusion. X-ray diffraction data have been collected using synchrotron radiation from crystals of both the native and a selenomethionine (SeMet) derivative of the protein. The native crystal form belongs to space group P2₁ and data were collected to a resolution of 2.2 Å. Two crystal forms of the SeMet protein have been obtained and were found to belong to space groups P1 and P2₁; data have been recorded to 2.0 and 1.7 Å resolution, respectively, for the two crystal forms. Three-wavelength MAD data were collected to 1.7 Å for the SeMet derivative crystal, which is isomorphous with the native P2₁ crystal.