CD Studies on aPNA-DNA Complexes

CD spectroscopy has been used extensively to study peptide-nucleic acid interactions. Conformation changes induced by either the peptide or nucleic acid can be detected readily using this spectroscopic technique. Although the CD spectra of 

CD spectra were recorded first for mixtures of aPNA C5(b2)-i-DNA dJTAjGsAjT) and CCTCC(b2) 4-d(A3GGAGGA3) at different molar ratios (Fig. 5.6A). A plot of the CD intensity at 258 nm with respect to the mole percentage of aPNA showed two lines of opposite but unequal slope that intersect at a 1 1 molar ratio of the aPNA and DNA strands. We also noted that the complex formed between T5(b2)- 

These CD studies confirmed the binding stoichiometries of our aPNA-DNA complexes and provided further support for our binding model. Comparisons between the CD spectra of the individual components and the aPNA DNA complex suggest a template effect (not unhke that observed with certain DNA-binding proteins) where the components induce mutual conformational changes upon their interaction with each other. 

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