CD studies on the conformation of some deoxyoligonucleotides containing adenine and thymine residues

CD studies of the deoxyoligomer series d(pT)(n) and d(pA)(n) show increasing CD maxima for oligo (dT)'s with chain length variation from two to seven, while oligo (dA)'s exhibit a decreasing CD maximum. Concentrated solutions of NaClO(4) cause a decrease in the CD of longer oligo (dT)'s towards the CD of d(pT)(2) which is different from oligo dA's. Probably base-sugar interactions are important in the observed conformational effects. The chemically synthesized oligomers dpApApTpT and dpTpApTpA show deviations in their CD spectra which reflect a dominating conformational effect of d(pA)(2) in the former but not in the alternating isomer.