Three protein fragments of different sizes which contain the DNA binding domain of transcription factor GAL4 from Saccharomyces cerevisiae have been expressed in functional forms in Escherichia coli. DNase I footprinting and gel retardation assays showed that the purified proteins bound to the same DNA sequence on the gal1-gal10 promoter as intact GAL4 does. Denaturation-refolding experiments demonstrated that Zn(II) is necessary for maintenance of the conformation of the DNA binding domain of GAL4, as judged on UV-CD and 1H-NMR measurements, as well as for specific DNA binding.
- DNA binding domain
- Zn-dependent conformation