[Packing of binding stained DNA strands in bacteriophage lambda]

Distribution of stainable DNA strands in phage lambda has been studied by polarized fluorescence. The effect of tight DNA-packing on fluorescence depolarization of complex dye-DNA was calculated. It is shown that stainable DNA in the phage is not concentrated in the central region. The arrangement of acridine orange molecules on the surface layers of the packed DNA is the most probable one.