Abstract
A large number of animal DNA-binding proteins contain several repeats of DNA-binding units, such as "zinc finger motif" and "Myb-related motif", in a tandem array. These repeats together recognize DNA in a sequence-specific manner. By contrast, plants have many proteins, particularly involved in plant-specific processes, which contain a single DNA-binding unit or a limited number of the units separated by long spacers. These observations raise intriguing questions. Is the plant DNA-binding unit related to the corresponding unit in the cluster-type animal protein at the level of molecular structure? Does an isolated unit in plant proteins bind to DNA in the same mode as the corresponding unit of the cluster-type protein? Here we present results of structural and functional studies on plant DNA-binding proteins, the GARP family of the Myb-related motifs of Arabidopsis response regulators and the EPF family of petunia containing zinc finger motifs, carried out to answer these questions.
