Functional domains of DnaA proteins

Functional domains of the initiator protein DnaA of Escherichia coli have b een defined. Domain 1, amino acids 1-86, is involved in oligomerization and in interaction with DnaB. Domain 2, aa 87-134, constitutes a flexible loop . Domain 3, aa 135-373, contains the binding site for ATP or ADP, the ATPas e function, a second interaction site with DnaB, and is required for local DNA unwinding. Domain 4 is required and sufficient for specific binding to DNA. We show that there are three different types of cooperative interactio ns during the DNA binding of DnaA proteins from E. coli, Streptomyces livid ans, and Thermus thermophilus: i) binding to distant binding sites; ii) bin ding to closely spaced binding sites; and iii) binding to non-canonical bin ding sites. (C) 1999 societe francaise de biochimie et biologie moleculaire /Editions scientifiques et medicales Elsevier SAS.