Structure-function study of peroxidase-like G-quadruplex-hemin complexes.

The structure-function relationship of G-quadruplex-hemin complexes with peroxidase activity was studied by comparing peroxidase activity and circular dichroism (CD) spectra of 22 oligonucleotides with the sequence of d(G(2)T(n))(3)G(2), d(G(3)T(n))(3)G(3) (n = 1-4) and dG(3)T(i)G(3)T(j)G(3)T(k)G(3). According to the experimental results, some conclusions can be drawn, such as the addition of hemin may promote the conversion of some G-quadruplexes from antiparallel structures to parallel structures; the formation of G-quadruplexes is a crucial factor in determining the peroxidase activity of G-quadruplex-hemin complexes; and the complexes formed by hemin and parallel G-quadruplexes have much higher peroxidase activity than those formed by hemin and antiparallel G-quadruplexes.