Study on the electrocatalytic activity of human telomere G-quadruplex–hemin complex and its interaction with small molecular ligands

Here we report that human telomere guanine-rich sequence AGGG(TTAGGG)3 (G4) and hemin can form a G-quadruplex–hemin complex (GHC) which exhibits good electrochemical characteristics. The redox signals of the complex and the electrocatalytic activities toward the reduction of hydrogen peroxide have been investigated. Based on this, two small molecular ligands of G-quadruplex, also known as candidates of anticancer drug, 5,10,15,20-tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) and N,N′-bis[2-(1-piperidino)-ethyl]-3,4,9,10-perylenetetracarboxylic diimide (PIPER), were used as model molecules to interrogate their binding activities and their effects on electrochemical behavior of GHC. Besides, spectrometric methods were simultaneously used to verify the interactions and binding stoichiometry between these molecules and GHC. These studies may provide a new way to characterize the structure and properties of human telomere and may have further applications.