Kinetically Governed Formation of d(G4T2G4) Assemblies.
The most frequently appearing form of DNA is a double helical structure in which two single strands are held together by Watson-Crick base pairs. In addition, guanine rich DNA sequences are known to adopt several unusual structures with G-quartet as a basic repeating motif. Recently large self-assembling nanostructures, called G-wires have become of great interest because of their potential use in molecular electronics. To better understand the forces driving structural transitions of G-wires formed from d(G4T2G4) oligonucleotide in Na+ solutions, we employed a number of techniques such as UV and CD spectroscopy, differential scanning calorimetry (DSC), gel electrophoresis, small angle X-ray scattering (SAXS) and dynamic light scattering (DLS). All the experimental techniques showed that thermally induced folding transitions depend on the cooling rate. In addition, DSC shows that thermally induced unfolding transition depends on heating rate, thus leading to the conclusion that structural transitions of d(G4T2G4) are kinetically governed processes.
Iztok
I
Prislan
Andrej
A
Jamnik
Matija
M
Tomšič