Phasing of RecA monomers on quasi-random DNA sequences.

We show that some arbitrarily chosen DNA sequences have the ability to influence the positioning of RecA monomers in RecA-DNA complexes. The preferential phase of binding of RecA monomers is shown to depend on the DNA sequence and its nucleotide composition. A simple rearrangement of bases in a limited DNA stretch influences the phasing of RecA monomers. On the other hand, that some features of DNA sequences interfere with the phasing on specific DNA sites demonstrates the existence of mechanisms for both positive and negative regulation of phasing on natural DNAs. The possible role of phasing of RecA monomers on DNA is discussed.