STRUCTURE-BASED DESIGN OF A DIMERIC ZINC-FINGER PROTEIN

Designing DNA-binding proteins with novel sequence specificities may p rovide valuable tools for biological research and gene therapy. Comput er modeling was used to design a dimeric zinc finger protein, ZFGD1, c ontaining zinc fingers 1 and 2 from Zif268 and a portion of the dimeri zation domain of GAL4. ZFGD1 binds with high affinity and specificity to the predicted binding site, which contains two 6 base-pair symmetry -related zinc finger subsites separated by a 13 base-pair spacer, The DNA-binding specificity of this fusion protein is determined primarily by the zinc fingers and can be systematically altered through the sub stitution of the zinc fingers with variants selected by phage display. This zinc finger-GAL4, fusion may serve as a prototype for designed D NA-binding proteins that could exploit advantages of home-and heterodi mer formation, and the adaptability of the Cys(2)His(2) zinc finger mo tif, to target virtually any site in the genome.