Crystallization and preliminary X-ray crystallographic studies of DesR, a thermosensing response regulator in a two-component signalling system from Streptococcus pneumoniae

Abstract

The response regulator DesR, which activates the transcription of the des gene by binding to a regulatory region, is essential for controlling the fluidity of membrane phospholipids. DesR from Streptococcus pneumoniae was over-expressed in Escherichia coli. The protein was purified and crystallized for structural analysis. Diffraction data were collected to 1.7 angstrom resolution using synchrotron radiation and the crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 46.91, b = 71.38, c = 117.73 angstrom. Assuming the presence of a dimer in the asymmetric unit, this corresponds to a V-M of 2.21 angstrom(3) Da(-1).