DNA is a promising material for the construction of a biosensor or bioindicator because its structure is sensitive to the binding of cofactors. We designed DNA which exhibit a novel structural transition from a Watson-Crick antiparallel duplex to a parallel Hoogsteen duplex as the pH changes from pH 7.0 to 5.0. By labeling this DNA for fluorescence resonance energy transfer, we were able to develop a sensitive pH indicator that can detect changes between pH 7.0 and 5.0. Moreover, the DNA was able to observe the pH changes in living cells during apoptosis as an easily detected change in color. We expect that this novel DNA-based pH sensor will be used as a probe for investigating biological processes in living cells.
|
