Sedimentation velocity analysis of TMPyP4-induced dimer formation of human telomeric G-quadruplex

Yating Gao,Xiaodong Ye,Tianlei Guang

doi:10.1039/c7ra07758k

Abstract

Analytical ultracentrifugation sedimentation velocity (AUC-SV) was used to study the interactions between TMPyP4 and AGGG(TTAGGG)3 (Tel22) and the TMPyP4-induced dimer formation of G-quadruplex.

Highlights

G-quadruplex, a four-stranded DNA structure consisting of pplanar G-quartets, has received much interest due to its potential application as a target in cancer therapy.[1,2,3,4,5,6] Some molecules such as proteins, drugs, and ligands can bind to Gquadruplex, adjust its structure and in uence its function.[7,8,9,10,11,12,13] For example, 5,10,15,20-tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) (Scheme 1(a)), a well-studied ligand, has shown the abililty to stabilize the structure of human telomeric G-quadruplex and inhibit the activity of telomerase.[14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38] Until now, different techniques have been used to study the interactions between G-quadruplex and this ligand, such as UV-vis absorption,[17,19,23] circular dichroism (CD),[17,26,36] isothermal titration calorimetry (ITC),[36 ] uorescence/phosphorescence spectroscopy,[7,32,34] gel electrophoresis,[36] molecular modeling,[35,39] mass spectrometry,[11] nuclear magnetic resonance (NMR) spectroscopy,[40] X-ray crystallography,[21] and so on
We investigated the effect of 5,10,15,20-tetra-(N-methyl4-pyridyl)porphyrin (TMPyP4) (Scheme 1(a)) on the structure of G-quadruplex in aqueous solutions using analytical ultracentrifugation sedimentation velocity (AUC-Sedimentation velocity (SV)), polyacrylamide gel electrophoresis (PAGE), UV-vis spectrophotometry and circular dichroism (CD) spectroscopy
The results of AUC-SV show that the binding number of TMPyP4 per Tel[22] is affected by both concentration of TMPyP4 (CTMPyP4) and concentration of NaCl (CNaCl)

Summary

Introduction

G-quadruplex, a four-stranded DNA structure consisting of pplanar G-quartets, has received much interest due to its potential application as a target in cancer therapy.[1,2,3,4,5,6] Some molecules such as proteins, drugs, and ligands can bind to Gquadruplex, adjust its structure and in uence its function.[7,8,9,10,11,12,13] For example, 5,10,15,20-tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) (Scheme 1(a)), a well-studied ligand, has shown the abililty to stabilize the structure of human telomeric G-quadruplex and inhibit the activity of telomerase.[14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38] Until now, different techniques have been used to study the interactions between G-quadruplex and this ligand, such as UV-vis absorption,[17,19,23] circular dichroism (CD),[17,26,36] isothermal titration calorimetry (ITC),[36 ] uorescence/phosphorescence spectroscopy,[7,32,34] gel electrophoresis,[36] molecular modeling,[35,39] mass spectrometry,[11] nuclear magnetic resonance (NMR) spectroscopy,[40] X-ray crystallography,[21] and so on.

Results

Conclusion