A Proton-Fuelled DNA Nanomachine


  • We thank Drs. Paul Barker, Yamuna Krishnan-Ghosh, and Liming Ying for helpful discussions. Dr. Dongsheng Liu is supported by The Interdisciplinary Research Collaboration (IRC) in Nanotechnology.


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Making DNA blink: A molecular machine based on the DNA i-motif structure is driven by changing pH (see picture). At pH 5, oligonucleotide X* folds into the i-motif (closed state), and complementary strand Y adopts a random-coil structure. At pH 8, X* unfolds and forms an extended duplex with Y. This reversible process can be monitored by means of a rhodamine green label (green circle), whose fluorescence is quenched by a dabcyl moiety (gray circle) in the closed but not in the open state.