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. Author manuscript; available in PMC: 2008 Sep 25.

Published in final edited form as: Biochemistry. 2006 Apr 4;45(13):4141–4152. doi: 10.1021/bi052322r

Quality of the electron density and overall conformations of ANA- and FANA-modified duplexes. (A) Sum (2F_o-F_c) Fourier electron density (1.5 σ level) around residues 2′OMeA5 and aU6 in the A-ANA structure. Note the unstacking of bases as a result of a strong roll. (B) Sum (2F_o-F_c) Fourier electron density (1.5 σ level) around residues T7 and aU8 in the B-ANA2 structure. (C) The A-FANA1 duplex viewed into the major groove. Residues faT6 and faT16 are highlighted in magenta and 2′-fluorine atoms are green. (D) The B-ANA2 duplex viewed into the major groove. Residues aU8 and aU20 are highlighted in blue and 2′-oxygen atoms are red. (E) Different degrees of bending into the major groove exhibited by ANA- and FANA-modified DNA decamer duplexes: A-FANA1 (green) > A-FANA2 (red) > A-ANA (blue). The duplexes were superimposed by aligning the helical axes in their bottom halves (base pairs G1:C20 – T4:A17). The view is across the major (left) and minor (right) grooves and the molecular dyad is horizontal. 2′-Fluorine (A-FANA1 and A-FANA2) and 2′-oxygen atoms (A-ANA) are highlighted as spheres with matching colors.

Quality of the electron density and overall conformations of ANA- and FANA-modified duplexes. (A) Sum (2F_o-F_c) Fourier electron density (1.5 σ level) around residues 2′OMeA5 and aU6 in the A-ANA structure. Note the unstacking of bases as a result of a strong roll. (B) Sum (2F_o-F_c) Fourier electron density (1.5 σ level) around residues T7 and aU8 in the B-ANA2 structure. (C) The A-FANA1 duplex viewed into the major groove. Residues faT6 and faT16 are highlighted in magenta and 2′-fluorine atoms are green. (D) The B-ANA2 duplex viewed into the major groove. Residues aU8 and aU20 are highlighted in blue and 2′-oxygen atoms are red. (E) Different degrees of bending into the major groove exhibited by ANA- and FANA-modified DNA decamer duplexes: A-FANA1 (green) > A-FANA2 (red) > A-ANA (blue). The duplexes were superimposed by aligning the helical axes in their bottom halves (base pairs G1:C20 – T4:A17). The view is across the major (left) and minor (right) grooves and the molecular dyad is horizontal. 2′-Fluorine (A-FANA1 and A-FANA2) and 2′-oxygen atoms (A-ANA) are highlighted as spheres with matching colors.