Selective Binding of Zn²⁺ Complexes to Non-Canonical Thymine or Uracil in DNA or RNA

This chapter discusses Zn2+ macrocyclic complexes that bind to DNA and RNA with an emphasis on the recognition of non-canonical deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) structures. It discusses additional considerations of the important energetic factors contributing to binding. The chapter describes the recognition of two common types of structures that involve non-canonical thymine or uracil. It focuses on, using structural information from nuclear magnetic resonance (NMR) spectroscopy to rationalize the selectivity of binding of monomelic Zn2+ complexes to thymine bulges in DNA. The chapter also focuses on binding interactions of Zn2+ complexes that contain a pendent two-ring aromatic group. These complexes have the highest selectivity for binding to non-canonical thymine in DNA or uracil in RNA bulges. An additional consideration is that selectivity toward non-canonical thymine or uracil may be improved by decreasing binding strength of Zn2+ complexes to double-stranded DNA or RNA, respectively.