2024-03-29T04:47:30Zhttps://riubu.ubu.es/oai/requestoai:riubu.ubu.es:10259/47462022-04-29T12:02:48Zcom_10259_4365com_10259_5086com_10259_2604com_10259_4883col_10259_4366col_10259_4884
Pérez Arnáiz, Cristina
Busto Vázquez, Natalia
Santolaya, Javier
Leal Villalba, José María
Barone, Giampaolo
García Ruiz, Begoña
2018-03-08T09:23:37Z
2019-03-01T03:45:06Z
2018-03
0304-4165
http://hdl.handle.net/10259/4746
10.1016/j.bbagen.2017.10.020
Background: Stabilization of G-quadruplex helices by small ligands has attracted growing attention because they
inhibit the activity of the enzyme telomerase, which is overexpressed in> 80% cancer cells. TMPyP4, one of the
most studied G-quadruplex ligands, is used as a model to show that the ligands can exhibit different binding
features with different conformations of a human telomeric specific sequence.
Methods: UV–Vis, FRET melting Assay, Isothermal Titration Calorimetry, Time-resolved Fluorescence lifetime,
T-Jump and Molecular Dynamics.
Results: TMPyP4 yields two different complexes with two Tel22 telomeric conformations in the presence of Na+
or K+. T-Jump kinetic experiments show that the rates of formation and dissociation of these complexes in the
ms time scale differ by one order of magnitude. MD simulations reveal that, in K+ buffer, “hybrid 1” conformation
yields kinetic constants on interaction with TMPyP4 one order lower than “hybrid 2”. The binding
involves π–π stacking with external loop bases.
Conclusions: For the first time we show that for a particular buffer TMPyP4 interacts in a kinetically different
way with the two Tel22 conformations even if the complexes formed are thermodynamically indistinguishable.
General significance: G-quadruplexes, endowed with technological applications and potential impact on regulation
mechanisms, define a new research field. The possibility of building different conformations from same
sequence is a complex issue that confers G-quadruplexes very interesting features. The obtaining of reliable
kinetic data constitutes an efficient tool to determine reaction mechanisms between conformations and small
molecules.
eng
http://creativecommons.org/licenses/by-nc-nd/4.0/
info:eu-repo/semantics/openAccess
Attribution-NonCommercial-NoDerivatives 4.0 International
Tel22 conformations
TMPyP4
Fast reactions
Molecular dynamics
Kinetic evidence for interaction of TMPyP4 with two different G-quadruplex conformations of human telomeric DNA
info:eu-repo/semantics/article