USE OF A FUSION PROTEIN TO OBTAIN CRYSTALS SUITABLE FOR X-RAY-ANALYSIS - CRYSTALLIZATION OF A GST-FUSED PROTEIN CONTAINING THE DNA-BINDING DOMAIN OF DNA REPLICATION-RELATED ELEMENT-BINDING FACTOR, DREF

Crystals of glutathione-S-transferase (GST)-fused protein containing t he DNA-binding domain of DNA replication-related element-binding facto r, DREF, were obtained under crystallization conditions similar to tho se for GST. Preliminary X-ray crystallographic analysis revealed that crystals of the GST-fused protein belong to space group P6(1)22 or P6( 5)22 with unit cell dimensions a = b = 140.4 Angstrom, c = 93.5 Angstr om and gamma = 120 degrees, having one molecule in the crystallographi c asymmetric unit. The crystals diffract to 2.5 Angstrom resolution. T he cell dimensions are related to those of GST crystals thus far repor ted. Crystallization of the DNA-binding domain that was cleaved from t he fused protein by thrombin was also carried out using several method s under numerous conditions, but efforts to produce well-ordered large crystals were unsuccessful. A possible application of GST-fusion prot eins for small target proteins or domains to obtain crystals suitable for X-ray structure determination is proposed.