REFINED SOLUTION STRUCTURE OF THE DNA-BINDING DOMAIN OF GAL4 AND USE OF (3)J(CD-113,H-1) IN STRUCTURE DETERMINATION

We have refilled the solution structure of cadmium-bound GAL4 and pres ent its N-15 and H-1 NMR assignments. The root-mean-square (rms) devia tion to the average structure was 0.4 +/- 0.05 Angstrom for backbone a toms, and 0.9 +/- 0.1 Angstrom for all heavy atoms. The three-bond het eronuclear (3)J(Cd-113,H-1) coupling constants were found to disobey a Karplus-type relationship, which was attributable to the unusual cons traints imposed by the bimetal-thiolate cluster in GAL4. We conclude t hat the structural parameters that correlate to (3)J(Cd-113,H-1) are c omplex.