The Chirality of the Cholesteric Phases of DNA and G-Wires: Its Connection to their Molecular Structures

✍ Scribed by Gloria Proni; Giovanni Gottarelli; Paolo Mariani; Gian Piero Spada

• Book ID: 101376035
• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 283 KB
• Volume: 6
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/1521-3765(20000901)6:17<3249::aid-chem3249>3.0.co;2-f

✦ Synopsis

While the handedness of the cholesteric phases formed by assembled guanosine derivatives (G-wires) follow the correlation right-handed helices 3 right-handed cholesterics (left-handed 3 left-handed), the cholesteric phase formed by B-DNA (right-handed helix) is left-handed. This apparent discrepancy is overcome by considering pitch (p) variations with temperature. Plots of p À1 versus T À1 have, in fact, the same trend (positive intercept and negative slope) in the case of right-handed G-wires and B-DNA, while for the left-handed G-wire of deoxyguanosine monophosphate (dGMP), the opposite behavior is observed (negative intercept and posi-tive slope). Therefore, the relation between molecular handedness and cholesteric helicity cannot, in general, be assessed by using measurements based on a single temperature; hence the temperature variation of the cholesteric parameters should be investigated. In all cases there is no remarkable salt effect on the cholesteric parameters.