(A–C) CD spectra of the C8-AF-modified single strand (---) and duplex (---) oligonucleotides at positions G1 (2b, panel A), G2 (3b, panel B), and G3 (4b, panel C) of the NarI restriction sequence. (D–F) UV spectra of the C8-AF-modified single strand (–––) and double strand (—) oligonucleotides at positions G1 (2b, panel D), G2 (3b, panel E), and G3 (4b, panel F) of the NarI restriction sequence.