Issue 2, 2021

Structural motifs and intramolecular interactions in non-canonical G-quadruplexes

Abstract

Guanine(G)-rich DNA or RNA sequences can assemble or intramolecularly fold into G-quadruplexes formed through the stacking of planar G·G·G·G tetrads in the presence of monovalent cations. These secondary nucleic acid structures have convincingly been shown to also exist within a cellular environment exerting important regulatory functions in physiological processes. For identifying nucleic acid segments prone to quadruplex formation, a putative quadruplex sequence motif encompassing closely spaced tracts of three or more guanosines is frequently employed for bioinformatic search algorithms. Depending on the number and type of intervening residues as well as on solution conditions, such sequences may fold into various canonical G4 topologies with continuous G-columns. On the other hand, a growing number of sequences capable of quadruplex formation feature G-deficient guanine tracts, escaping the conservative consensus motif. By folding into non-canonical quadruplex structures, they adopt unique topologies depending on their specific sequence context. These include G-columns with only two guanines, bulges, snapback loops, D- and V-shaped loops as well as interlocked structures. This review focuses on G-quadruplex species carrying such distinct structural motifs. It evaluates characteristic features of their non-conventional scaffold and highlights principles of stabilizing interactions that also allow for their folding into stable G-quadruplex structures.

Graphical abstract: Structural motifs and intramolecular interactions in non-canonical G-quadruplexes

Article information

Article type
Review Article
Submitted
18 nov. 2020
Accepted
14 janv. 2021
First published
22 janv. 2021
This article is Open Access
Creative Commons BY license

RSC Chem. Biol., 2021,2, 338-353

Structural motifs and intramolecular interactions in non-canonical G-quadruplexes

J. Jana, S. Mohr, Y. M. Vianney and K. Weisz, RSC Chem. Biol., 2021, 2, 338 DOI: 10.1039/D0CB00211A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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