Quadruplex Nucleic Acids

Volume 330 of the series Topics in Current Chemistry pp 67-86


Circular Dichroism of Quadruplex Structures

  • Antonio RandazzoAffiliated withDipartimento di Chimica Farmaceutica e Tossicologica, Università degli Studi di Napoli “Federico II” Email author 
  • , Gian Piero SpadaAffiliated withDipartimento di Chimica Organica “A. Mangini”, Alma Mater Studiorum-Università di Bologna
  • , Mateus Webba da SilvaAffiliated withSchool of Biomedical Sciences, University of Ulster


Circular dichroism (CD) is a widespread technique for studying the polymorphism of G-quadruplexes. In this chapter the CD spectral features characteristic of different folding topologies of G4-DNA are analyzed in terms of the sequence of the syn or anti glycosidic bond angle (GBA) within a quadruplex stem. Depending on the GBA sequence, the chiral disposition of two stacked guanines, adjacent along a strand, is different and this leads to a predictable contribution to the overall CD spectrum. The CD spectra of a series of G-quadruplexes, chosen as prototypal of the most common strand folding, are illustrated. The validity and the prediction power of the approach is corroborated by the analysis of CD spectra of structurally modified G4-DNA either with chemically modified guanines or polarity inversion site (5′-5′ or 3′-3′) along the strands or additional nucleobases contributing to the stacking.


Circular Dichroism G-quadruplex DNA RNA