Interaction of Cationic Manganese Porphyrin with G-Quadruplex Nucleic Acids Probed by Differential Labeling of the Two Faces of the Porphyrin

摘要

G-quadruplex nucleic acids have attracted much interest in recent years because they appear to be involved in the regulation of fundamental processes of life, in particular, those connected to the development of cancer. Several in vitro structures are now available. G-quadruplex nucleic acids consist of four strands of nucleic acids that form in guanine-rich DNA/RNA sequences with stretches of tandem guanine residues. The four strands are held together by a hydrogen-bonded arrangement of four guanines (the G-quartet unit). Stacking of planar consecutive G-quartets further stabilizes the G-quadruplex structures. G-quadruplex nucleic acids have four external grooves, and for those formed by intermolecular folding, they have also single-stranded loops connecting the guanine tracts. A central ionic channel with K~+ (and/or Na~+) ions exists in the core of the superimposed G-quartets. Their presence in human cells has recently been shown.