Examination of effect of thymine loop length on polymorphism of G-quadruplex.

Abstract

Structural polymorphism is one of the important issue with regard to G-quadruplexes because the structural diversity may significantly affect their biological functions in vivo and also their physical properties in nano-material. A series of oligonucleotides with four repeat guanines sequences, d(G4Tn)3G4 (where n = 1-6) were designed for this study to investigate the effect of the length of loop on the polymorphism of G-quadruplex and the effect of the structure of the resulting G-quadruplex on its melting point. Via CD spectroscopy and comparison with the known CD spectrums of previously studied G-quadruplexes, and with the help of PAGE analysis, the structures of the G-quadruplexes could be predicted. A trend was also observed for these oligonucleotides while varying their T-loop length and this will be analyzed in this study.