Compositions and methods are provided that reduce the time required for detection of botulinum neurotoxins in cell-based assays. In one aspect an isoquinolynyl compound can be used for this purpose. In such cell-based assays the cell can include an enzyme that facilitates degradation of the reporter significantly faster after the cleavage than before the cleavage, and presence of the Botulinum toxin correlates with reduction of the signal from a baseline signal. The cell can advantageously express both the construct that includes the reporter, and an enzyme that facilitates the degradation.

The present disclosure provides antibodies that specifically bind to botulinum neurotoxins (e.g., BoNT/A, BoNT/B, BoNT/C, BoNT/D, BoNT/E, BoNT/F, BoNT/G, etc.) and the epitopes bound by those antibodies. The antibodies and derivatives thereof that specifically bind to the neutralizing epitopes provided herein can be used to neutralize botulinum neurotoxin and are therefore also useful in the treatment of botulism.

Described are cell-based methods for detecting botulinum neurotoxin (BoNT) potency and/or activity in the absence of LD.sub.50 assays that rely upon large numbers of laboratory animals.

The present specification discloses SNAP-25 compositions, methods of making α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, methods of detecting BoNT/A activity, and methods of detecting neutralizing α-BoNT/A antibodies.

The present specification discloses SNAP-25 compositions, methods of making α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, methods of detecting BoNT/A activity, and methods of detecting neutralizing α-BoNT/A antibodies.

The invention describes methods and reagents useful for sequencing polypeptide molecules. The method comprises affixing a polypeptide to a substrate and contacting the polypeptide with a plurality of probes. Each probe selectively binds to an N-terminal amino acid or an N-terminal amino acid derivative. Probes bound to the polypeptide molecule are then identified before cleaving the N-terminal amino acid or N-terminal amino acid derivative of the polypeptide. Also provided are methods for the sequencing a plurality of polypeptide molecules in a sample and probes specific for N-terminal amino acids or N-terminal amino acid derivatives.

The present disclosure provides antibodies that specifically bind to botulinum neurotoxins (e.g., BoNT/A, BoNT/B, BoNT/C, BoNT/D, BoNT/E, BoNT/F, BoNT/G, etc.) and the epitopes bound by those antibodies. The antibodies and derivatives thereof that specifically bind to the neutralizing epitopes provided herein can be used to neutralize botulinum neurotoxin and are therefore also useful in the treatment of botulism.

The present specification discloses SNAP-25 compositions, methods of making α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, α-SNAP-25 antibodies that bind an epitope comprising a carboxyl-terminus at the P.sub.1 residue from the BoNT/A cleavage site scissile bond from a SNAP-25 cleavage product, methods of detecting BoNT/A activity, and methods of detecting neutralizing α-BoNT/A antibodies.

The present disclosure provides antibodies that specifically bind to botulinum neurotoxins (e.g., BoNT/A, BoNT/B, BoNT/C, BoNT/D, BoNT/E, BoNT/F, BoNT/G, etc.) and the epitopes bound by those antibodies. The antibodies and derivatives thereof that specifically bind to the neutralizing epitopes provided herein can be used to neutralize botulinum neurotoxin and are therefore also useful in the treatment of botulism.

Disclosed herein is a botulinum neurotoxin (BoNT) polypeptide with a modified receptor binding domain (HC) having one or more amino acid mutations that modify the binding of the BoNT to the receptor. Specific mutations and combinations of mutations are also disclosed. Isolated modified HC, polypeptides comprising the modified HC, chimeric molecules, pharmaceutical compositions, and methods of making and using the same are also disclosed. Methods of identifying additional such modified receptor binding domains, are further disclosed.