Abstract
Here we describe a novel and efficient procedure for preparation of long uniform G4-DNA wires. The procedure includes (i) enzymatic synthesis of double-stranded DNA molecules consisting of long (up to 10,000 bases), continuous G strands and chains of complementary (dC)20-oligonucleotides, poly(dG)-n(dC)20; (ii) size exclusion HPLC separation of the G strands from the (dC)20 oligonucleotides in 0.1 M NaOH; and (iii) folding of the purified G strands into G4-DNA structures by lowering the pH to 7.0. We show by atomic force microscopy (AFM) that the preparation procedure yielded G4-DNA wires with a uniform morphology and a narrow length distribution. The correlation between the total amount of nucleotides in the G strands and the contour length of the G4-DNA molecules estimated by AFM suggests monomolecular folding of the G strands into quadruplex structures. The folding takes place either in the presence or in the absence of stabilizing ions (K+ or Na+). The addition of these cations leads to a dramatic change in the circular dichroism spectrum of the G4-DNA.
Original language | English |
---|---|
Pages (from-to) | 71-78 |
Number of pages | 8 |
Journal | Analytical Biochemistry |
Volume | 374 |
Issue number | 1 |
DOIs | |
State | Published - 1 Mar 2008 |
Bibliographical note
Funding Information:This work was supported by European Grants for Future and Emerging Technologies (IST-2001-38951 [“DNA-Based Nanowires”] and FP6-291292 [“DNA-Based Nanodevices”]).
Keywords
- AFM
- CD spectroscopy
- Enzymatic synthesis
- Folding of poly(dG) strands
- G4-DNA nanowires