title: Role of Alkali Metal Ions in G-Quadruplex Nucleic Acid Structure and Stability.
abstract: G-quadruplexes are guanine-rich nucleic acids that fold by forming successive quartets of guanines (the G-tetrads), stabilized by intra-quartet hydrogen bonds, inter-quartet stacking, and cation coordination. This specific although highly polymorphic type of secondary structure deviates significantly from the classical B-DNA duplex. G-quadruplexes are detectable in human cells and are strongly suspected to be involved in a number of biological processes at the DNA and RNA levels. The vast structural polymorphism exhibited by G-quadruplexes, together with their putative biological relevance, makes them attractive therapeutic targets compared to canonical duplex DNA. This chapter focuses on the essential and specific coordination of alkali metal cations by G-quadruplex nucleic acids, and most notably on studies highlighting cation-dependent dissimilarities in their stability, structure, formation, and interconversion. Section 1 surveys G-quadruplex structures and their interactions with alkali metal ions while Section 2 presents analytical methods used to study G-quadruplexes. The influence of alkali cations on the stability, structure, and kinetics of formation of G-quadruplex structures of quadruplexes will be discussed in Sections 3 and 4. Section 5 focuses on the cation-induced interconversion of G-quadruplex structures. In Sections 3 to 5, we will particularly emphasize the comparisons between cations, most often K(+) and Na(+) because of their prevalence in the literature and in cells.
authors: ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France.|ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France.
authors: Eric
authors: E
authors: Largy
authors: ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. jean-louis.mergny@inserm.fr.|ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France. jean-louis.mergny@inserm.fr.
authors: Jean-Louis
authors: JL
authors: Mergny
authors: ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. valerie.gabelica@inserm.fr.|ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France. valerie.gabelica@inserm.fr.
authors: Valérie
authors: V
authors: Gabelica
mesh_terms: D002412:Cations; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D008672:Metals, Alkali / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry*
chemical_list: D002412:Cations; D008672:Metals, Alkali; D012313:RNA; D004247:DNA
keywords: DNA; Folding; G-quadruplex; G-quartet; Interconversion; Metal ions; Methods; RNA; Stability; Structure