Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains

摘要: Abstract We now recognize three distinct motifs of DNA-binding zinc proteins: (i) fingers, (ii) clusters, and (iii) twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses proteins have not been available to serve as standards reference for the binding sites these families proteins. Those domains fungal transcription factor GAL4 rat glucocorticoid receptor are first determined. Both contain two sites, in both, cysteine residues sole ligands. In GAL4, atoms bound six which form a "zinc cluster" akin that metallothionein; distance between is approximately 3.5 A. receptor, each atom four residues; interatomic zinc-zinc 13 A, this instance, twist" represented by helical DNA recognition site located atoms. Zinc clusters twists here recognized distinctive containing multiple For native fingers," structural data do exist yet; consequently, distances known. As further become available, functional significance different their other participating transmission genetic message will apparent.