Stabilization vs. destabilization of G-quadruplex superstructures: the role of the porphyrin derivative having spermine arms

D'Urso, A
Randazzo, R
Rizzo, V
Gangemi, C. M. A
ROMANUCCI, VALERIA
ZARRELLI, ARMANDO
Tomaselli, G
Milardi, D
BORBONE, NICOLA
Purrello, R
PICCIALLI, GENNARO
DI FABIO, GIOVANNI
OLIVIERO, GIORGIA

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Publication date

January 2017

DOI

10.1039/c7cp02816d

ISSN

1463-9076

Abstract

The interaction of the porphyrin derivative H2TCPPSpm4, having spermine pendants in the four meso positions, with the G-quadruplex (GQ) structure formed by the DNA aptamer TGGGAG has been investigated by means of UV, electronic circular dichroism and PAGE studies. The results reported here demonstrate that the porphyrin derivative is capable of stabilizing or destabilizing the higher-ordered structures of parallel GQs, depending on the method used to reach their relative stoichiometry (titration vs. single addition). Noteworthily, when two equivalents of H2TCPPSpm4 were mixed directly with one equivalent of the (TGGGAG)4 GQ to reach a 2 : 1 H2TCPPSpm4 : GQ ratio T1/2 higher than 80 °C was also observed confirming the presence of higher-orde...