Cloning, expression, crystallization and crystallographic analysis of CouR fromRhodopseudomonas palustris
CouR fromRhodopseudomonas palustrisis a member of the MarR transcriptional regulator family. It regulates the expression of CouA and CouB, enzymes that are involved in the degradation ofp-coumarate.In vivo, CouR binds to a DNA fragment containing thecouABpromoter and suppresses the expression of CouA and CouB, while binding ofp-coumaroyl-CoA attenuates its affinity towards DNA and activates the expression of CouA and CouB. Here, the crystallization and X-ray diffraction analyses of CouR alone and in complex withp-coumaroyl-CoA are reported. Apo and ligand-complexed CouR crystals diffracted to 2.5 and 3.3 Å resolution, respectively. The crystals of apo CouR belonged to space groupP22121, with unit-cell parametersa= 62.78,b = 76.15,c = 87.38 Å, whereas the crystals of the CouR–ligand complex belonged to space groupP212121, with unit-cell parametersa= 61.37,b= 69.82,c = 70.32 Å. The crystals were predicted to contain two CouR molecules or CouR–ligand complexes per asymmetric unit.