Molecular Recognition Of G-Quadruplex Dna By Pheophorbide A

Pheophorbide a (Phed-a), a naturally occurring chlorophyll catabolite, has been receiving much attention as a biologically-derived photosensitizer in photodynamic therapy (PDT) because of its high phototoxicity even in anoxic environments. Interaction of phed-a with G-quadruplex DNAs possessing a variety of folding topologies has been investigated to elucidate the molecular recognition of G-quadruplex DNA by phed-a, which is crucial to determine its PDT efficacy in tumor hypoxia. We found that phed-a binds selectively to the 3'-terminal G-quartet of parallel G-quadruplex DNAs.