Purification, crystallization and preliminary X-ray crystallographic analysis of the ETS domain of human Ergp55 in complex with the cfos promoter DNA sequence.

The Ergp55 protein belongs to the Ets family of transciption factors. The Ets transcription factors are involved in various developmental processes and the regulation of cancer metabolism. They contain a highly similar DNA-binding domain known as the ETS domain and have diverse functions in oncogenesis and physiology. The Ets transcription factors differ in their DNA-binding preference at the ETS site and the mechanisms by which they target genes are not clearly understood. To understand its DNA-binding mechanism, the ETS domain of Ergp55 was expressed and purified. The ETS domain was crystallized in the native form and in complex forms with DNA sequences from the E74 and cfos promoters. An X-ray diffraction data set was collected from an ETS-cfos DNA complex crystal at a wavelength of 0.9725 Å on the BM14 synchrotron beamline at the ESRF, France. The ETS-cfos DNA complex crystal belonged to space group C222(1), with four molecules in the asymmetric unit. For structure analysis, initial phases for the ETS-cfos DNA complex were obtained by the molecular-replacement technique with Phaser in the CCP4 suite using the coordinates of Fli-1 protein (PDB entry 1fli) and cfos DNA (PDB entry 1bc7) as search models. Structure analysis of the ETS-cfos DNA complex may possibly explain the DNA-binding specificity and its mechanism of interaction with the ETS domain of Ergp55.