Nov 5, 2018

Spectroscopic study on binding of cationic Pheophorbide-a to antiparallel quadruplex Tel22

BioRxiv : the Preprint Server for Biology
Olga A. RyazanovaVictor A. Karachevtsev

Abstract

Binding of water-soluble cationic Pheophorbide- a derivative (CatPheo- a ) to Na+-stabilized antiparallel quadruplex formed by 22-mer oligonucleotide d[AG3(T2AG3)3], a fragment of human telomeric DNA (Tel22, PDB ID: 143D), has been examined using experimental techniques of absorption and polarized fluorescent spectroscopy as well as absorption melting. The binding affinity of CatPheo- a to Tel22 was studied in titration experiments registering the dependence of the dye fluorescence intensity and polarization degree on molar phosphate-to-dye ratio ( P/D ). CatPheo- a was found to bind effectively to the quadruplex, and two competitive binding modes were detected. The first one predominates at the dye excess and results in the fluorescence quenching, whereas the second one is preferential at the biopolymer excess and results in the enhancement of pheophorbide emission. The effect of CatPheo- a on thermodynamic parameters of Tel22 quadruplex unfolding was estimated using a two-state model. It was found that CatPheo- a destabilizes the quadruplex structure of Tel22 slightly decreasing its 4→1 transition midpoint temperature, gives destabilizing increment into Gibbs standard free energy and 2-fold decrease in the equilibrium quadrup...Continue Reading

  • References
  • Citations

References

  • We're still populating references for this paper, please check back later.
  • References
  • Citations

Citations

  • This paper may not have been cited yet.

Mentioned in this Paper

Study
Ethanol
Ethanol Measurement
Molecular Probe Techniques
Biopolymers
Phosphate Measurement
Iron Deficiency
Fluorescence Spectroscopy
Fluorescent stain
Soluble

About this Paper

Related Feeds

BioRxiv & MedRxiv Preprints

BioRxiv and MedRxiv are the preprint servers for biology and health sciences respectively, operated by Cold Spring Harbor Laboratory. Here are the latest preprint articles (which are not peer-reviewed) from BioRxiv and MedRxiv.