POLYDEOXYRIBOURIDYLIC ACID AND ITS COMPLEXES WITH POLYRIBO- AND DEOXYRIBOADENYLIC ACIDS

Polydeoxyribouridylic acid has been prepared (a) by polymerization of dUTP with the aid of terminal deoxynucleotidyl transferase, and (b) by deamination at elevated temperatures of polydeoxyribocytidylic acid. The two procedures gave similar products. Polydeoxyribouridylic acid is a random coil, with only a low degree of base stacking over the experimentally accessible range of temperature and ionic strength. It is hydrolysed to monomers by phosphodiesterase I. The complexes of polydeoxyribouridylic acid with polyriboadenylic acid and polydeoxyriboadenylic acid, and the various transitions and rearrangements undergone by these as a function of temperature and ionic strength, have been studied in detail. The results make possible, for the first time, a comparison of the properties of all the possible complexes, and the transitions and rearrangements, of the ribose and deoxyribose analogues of polyuridylic acid (and polythymidylic acid) with polyadenylic acid. The results of such comparisons are presented in graphical form and discussed in relation to the structure of both the synthetic polynucleotide complexes and natural nucleic acids. © 1969.