Seven essential questions on G-quadruplexes

Abstract

The helical duplex architecture of DNA was discovered by Francis Crick and James Watson in 1951 and is well known and understood. However, nucleic acids can also adopt alternative structural conformations that are less familiar, although no less biologically relevant, such as the G-quadruplex. G-quadruplexes continue to be the subject of a rapidly expanding area of research, owing to their significant potential as therapeutic targets and their unique biophysical properties. This review begins by focusing on G-quadruplex structure, elucidating the intermolecular and intramolecular interactions underlying its formation and highlighting several substructural variants. A variety of methods used to characterize these structures are also outlined. The current state of G-quadruplex research is then addressed by proffering seven pertinent questions for discussion. This review concludes with an overview of possible directions for future research trajectories in this exciting and relevant field.

Formation and Dissociation of the Interstrand i-Motif by the Sequences d(XnC4Ym) Monitored with Electrospray Ionization Mass Spectrometry

“…It can be concluded that the formation of tetramolecular i-motifs and G-quadruplexes follow different kinetic processes. The G-quadruplex may have a more stable structure when an appropriate cation is present for insertion between the G-tetrads [56][57][58]. For some sequences, the tetramolecular i-motif can be partly aggregated in a few hours after denaturation and slow cooling.…”

Plasmonic Circular Dichroism Study of Gold Nanorod-Quadruplex Nanobioconjugates

“…Since CD spectroscopy is very sensitive to base stacking [7][8][9], different configurations of quadruplex (such as parallel, antiparallel and hybrid forms) have their characteristic CD spectrum [8,9]. Fig.1 …”

“…Some of them have G-rich consensus sequences with ability to fold into the four-stranded structures known as Gquadruplexes. The repetitive part in this structure is a square plane called G-quartet, consisting of four guanines held together by guanine Hoogsteen hydrogen bonding [7]. In fact, G-quartet is a broad aromatic surface which is highly prone to π-π stacking interaction between adjacent surfaces [7].…”

“…The repetitive part in this structure is a square plane called G-quartet, consisting of four guanines held together by guanine Hoogsteen hydrogen bonding [7]. In fact, G-quartet is a broad aromatic surface which is highly prone to π-π stacking interaction between adjacent surfaces [7]. Apart from the order and number of guanine in the G-quadruplex prone oligonucleotide, quadruplex inducing factors i.e.…”

Explicit analytic equations for multimolecular thermal melting curves

“…Molecular multiplexes of molecularities larger than two exist for proteins [7,8] as well as for nucleic acids in large variety, e.g., DNA and RNA 3-, 4-, and 5-way junctions [9][10][11][12][13], triplex DNA/RNA [1,14], G-quadruplex DNA/RNA [14][15][16][17][18], i-motif DNA/RNA [18,19], or DNA-linked materials [20], and are an important part of current research. Their thermodynamic characterization on the basis of thermal melting experiments as in [2] is sparse.…”