Title
Synthesis and Label Free Characterization of a Bimolecular PNA Homo Quadruplex
Author
Brunella Pinto, Giulia Rusciano, Stefano D'Errico, Nicola Borbone, Antonio Sasso, Vincenzo Piccialli, Luciano Mayol, Giorgia Oliviero, Gennaro Piccialli
Year
2016
Journal
Biochimica et Biophysica Acta (BBA) - General Subjects
Abstract
G-quadruplex DNA is involved in many physiological and pathological processes. Both clinical and experimental studies on DNA G-quadruplexes are slowed down by their enzymatic instability. In this frame, more stable chemically modified analogs are needed. The bis-end-linked-(gggt)2 PNA molecule (BEL-PNA) was synthesized using in solution and solid phase synthetic approaches. Quadruplex formation was assessed by circular dichroism (CD) and surface enhanced Raman scattering (SERS). An unprecedented bimolecular PNA homo quadruplex is here reported. To achieve this goal, we developed a bifunctional linker that once functionalized with gggt PNA strands and annealed in K+ buffer allowed the obtainment of a PNA homo quadruplex. The identification of the strong SERS band at ~ 1481 cm− 1, attributable to vibrations involving the quadruplex diagnostic Hoogsteen type hydrogen bonds, confirmed the formation of the PNA homo quadruplex. By tethering two G-rich PNA strands to the two ends of a suitable bifunctional linker it is possible to obtain bimolecular PNA homo quadruplexes after annealing in K+-containing buffers. The formation of such CD-unfriendly complexes can be monitored, even at low concentrations, by using the SERS technique.
Instrument
J-1500
Keywords
Circular dichroism, DNA structure, Thermal stability, Biochemistry