Formation of G‑Wires: The Role of G:C-Base Pairing and G‑Quartet Stacking

• Published in: Journal of physical chemistry. C 2013-11, Vol.117 (44), p.23208-23215
• Main Authors: Ilc, Tina, Šket, Primož, Plavec, Janez, Webba da Silva, Mateus, Drevenšek-Olenik, Irena, Spindler, Lea
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Molecular electronics, nanoelectronics; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Physics; Quantum wires; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Structure of solids and liquids; crystallography
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp4019348

G-wireslong, continuous G-quadruplexesare a promising element for use in nanotechnology, particularly in molecular electronics. The pairing of G-quadruplex structures through complementary GC-termini was tested. We designed four analogous G-quadruplex-forming oligonucleotides with the same core sequence d(GG­T­G4­T­GG) and with different number and position of GC-ends. We used circular dichroism to determine the topology and relative orientation of G-quadruplexes, 1H NMR to identify Watson–Crick base pairing, and dynamic light scattering to examine the size of the G-quadruplex assemblies. The quadruplexes associated through GC-base pairs forming (G:C:G:C)-quartets and by stacking of unhindered terminal (G:G:G:G)-quartets. These two modes of association had different specificities: stacking occurred at both the 5′- and 3′- faces of the quadruplex, whereas GC-base pairing occurred only at the 5′-face of the quadruplex. These insights may be employed to design G-quadruplex-based nanowires or more complex architectures.