Statistical analysis of spectral mixing curve data

Characterization of imperfect DNA duplexes containing unpaired bases and non-Watson-Crick base pairs

Synthetic duplex DNAs of repeating sequence, such as poly d(TTC).poly d(GAA), were separated into their individual single strands. The various single strands complexed not only, as expected, with their complementary strands, but also with other non-complementary strands. Characterization of such complexes with respect to stoichiometry, Tm values and the dependence of Tm on NaCl concentration showed that a variety of unusual structures could be inferred at physiological salt concentrations. These included extrahelical thymines, G.T oppositions, A.C oppositions and T.C oppositions.

Azidopolynucleotides as photoaffinity reagents

Polynucleotides containing adenosine and 8-azidoadenosine or inosine and 8-azidoinosine residues have been prepared from mixtures of nucleoside diphosphates using polynucleotide phosphorylase from Escherichia coli. These copolymers can form complexes with polyuridylic or polycytidylic acids respectively. Single stranded poly(adenylic, 8-azidoadenylic acid) [poly(A,z8A)] has been used as a photoaffinity reagent to explore the subunit topography of RNA polymerase from E. coli.