Patent ID: 7709608

Claim:
A botulinum toxin substrate, comprising (a) a donor fluorophore; (b) an acceptor having an absorbance spectrum overlapping the emission spectrum of said donor fluorophore; and (c) BoNT/A recognition sequence comprising a BoNT/A P 5 -P 4 -P 3 -P 2 -P 1 -P 1 ′-P 2 ′-P 3 ′-P 4 ′-P 5 ′ cleavage site sequence, said BoNT/A P 5 -P 4 -P 3 -P 2 -P 1 -P 1 ′-P 2 ′-P 3 ′-P 4 ′-P 5 ′ cleavage site sequence intervening between said donor fluorophore and said acceptor; wherein either of said donor fluorophore, said acceptor, or both said donor fluorophore and said acceptor are genetically encoded; and wherein, under the appropriate conditions, resonance energy transfer is exhibited between said donor fluorophore and said acceptor.