The present invention provides for novel reagents whose fluorescence changes
upon cleavage or a change in conformation of a backbone. The reagents comprise
a backbone (e.g. nucleic acid, polypeptide, etc.) joining two fluorophores of the
same species whereby the fluorophores form an H-dimer resulting in quenching of
the fluorescence of the fluorophores. When the backbone is cleaved or changes conformation,
the fluorophores are separated, no longer forming an H-type dimer, and are de-quenched
thereby providing a detectable signal. The use of a single fluorophore rather than
an "acceptor-donor" fluoresecence resonance energy transfer system offers synthesis
and performance advantages.
