CRYSTAL-STRUCTURE OF A 5-FINGER GLI-DNA COMPLEX - NEW PERSPECTIVES ONZINC FINGERS

Zinc finger proteins, of the type first discovered in transcription fa ctor IIIA (TFIIIA), are one of the largest and most important families of DNA-binding proteins. The crystal structure of a complex containin g the five Zn fingers from the human GLI oncogene and a high-affinity DNA binding site has been determined at 2.6 angstrom resolution. Finge r one does not contact the DNA. Fingers two through five bind in the m ajor groove and wrap around the DNA, but lack the simple, strictly per iodic arrangement observed in the Zif268 complex. Fingers four and fiv e of GLI make extensive base contacts in a conserved nine base-pair re gion, and this section of the DNA has a conformation intermediate betw een B-DNA and A-DNA. Analyzing the GLI complex and comparing it with Z if268 offers new perspectives on Zn finger-DNA recognition.