Purification, crystallization and preliminary X-ray analysis of the BRCT domains of human 53BP1 bound to the p53 tumour suppressor

A complex of the DNA-binding domain of the tumour suppressor p53 bound to the BRCT domains of the p53-binding protein (53BP1) has been prepared and purified. Single crystals have been obtained using the microbatch technique with polyethylene glycol 4 kDa and ammonium sulfate. Crystals diffract X-rays to beyond 2.3 A and belong to the space group P2(1)2(1)2(1). Several complete data sets have been collected from a number of crystals, each with different unit-cell parameters. Partial structures have been produced by successful placement of two copies of the p53 core region into the asymmetric unit. There is clear evidence for the binding protein and a complete structure determination is under way.