Transformation in pneumococcus: existence and properties of a complex involving donor deoxyribonucleate single...

Donor deoxyribonucleic acid (DNA) single strands exist in a complex during the eclipse phase in pneumococcal transformation. This eclipse complex exhibited specific physical properties distinct from those of both pure DNA single strands and native DNA. These included a lower affinity for diethylaminoethyl-cellulose and hydroxylapatite than that of single-strand DNA, faster sedimentation than the DNA chains that it contains, and a buoyant density in Cs2SO4 lower than that of native DNA. The complex was dissociated by treatments with sodium dodecyl sulfate, NaOH, guanidine-hydrochloride, chloroform, and proteinase K but was insensitive to ribonuclease.