CONFORMATIONAL STUDIES OF THE SMALLEST STRUCTURAL MOTIFS OF DNA DETECTABLE VIA VIBRATIONAL CIRCULAR-DICHROISM - CYTIDYLYL-(3'-5')-GUANOSINE AND GUANYLYL-(3'-5')-CYTIDINE

The infrared absorption and vibrational circular dichroism (VCD) spectra of buffered aqueous solutions of cytidylyl(3'-5')-guanosine (5'(CG)3') and guanylyl-(3'-5')-cytidine (5'(GC)3') are reported. Under low ionic strength conditions, these dinucleotides exhibit VCD features that can be predicted qualitatively from structural data of (CG)(2) and (GC)(2) sequences of poly(dG-dC) poly(dG-dC), using the exciton model for infrared VCD intensities.