Initiation and Termination Events in Double Stranded ...x-DNA Replication.

The experiments reported in this paper lead to the following conclusions: 1. An endonucleolytic activity is associated with the "replication site" in Escherichia coli cells; this endonucleolytic activity attacks the complementary strand of the ψx replicative form DNA only. 2. the viral strand of the ψx-replicative form DNA remains circularly closed during the replication cycle; 3. In the immediate replication product both composing strands are linear; in circularization no strand is preferred; 4. A replication product with both strands closed is transiently found in a structural state which can be, under our experimental conditions, only partially denatured by alkali. Subsequently it is transformed to a typical supercoiled RFI structure. [ABSTRACT FROM AUTHOR]