Metal-Dependent DNA Base Pairing of 5-Carboxyuracil with Itself and All Four Canonical Nucleobases
Yusuke Takezawa, Akira Suzuki, Manabu Nakaya, Kotaro Nishiyama, Mitsuhiko Shionoya
Abstract
A 5-carboxyuracil (caU) nucleobase was found to pair not only with A (caU–A) by hydrogen bonding but also with other DNA nucleobases by metal coordination bonding. Metal-dependent formation of caU–CuII–caU, caU–HgII–T, caU–AgI–C, and caU–CuII–G pairs was demonstrated by duplex melting analysis and mass spectrometry. The duplexes containing caU–X (X = caU, T, C, and G) were significantly stabilized in the presence of the corresponding metal ions, while the DNA duplexes containing the caU–A pairs were destabilized by the addition of CuII. These results suggest that the hybridization partner of caU-containing DNA strands can be altered by metal complexation. As a result, this study provides a new direction to integrate caU nucleobases to construct diverse metallo-DNA supramolecules and metal-responsive DNA devices.