Discovery and design of novel inhibitors of botulinus neurotoxin A: targeted 'hinge' peptide libraries.
Intoxication by the zinc protease botulinus neurotoxin A (BoNT-A) results from cleavage of a single Q-R bond in the neuronal protein SNAP-25, which disables the docking mechanism required for neurotransmitter release. In the present study, potential inhibitors of BoNT-A were assessed from their effects on the BoNT-A cleavage of a synthetic 17-mer peptide (SNAP-25, residues 187-203) spanning the Q-R cleavage site. Compounds that inhibited BoNT-A included thiols (zinc chelators) such as dithiothreitol, dimercaptopropanesulfonic acid, mercaptosuccinic acid and captopril. In addition, compounds containing multiple acidic functions, such as the SNARE motif V2 (ELDDRADALQ), the tripeptide Glu-Glu-Glu and the steroid glycoside glycyrrhizic acid, were effective inhibitors. 'Hinge' peptide mini-libraries (PMLs) having the structure acetyl-X(1)-X(2)-linker-X(3)-X(4)-NH(2) or X(1)-X(2)-linker-X(3), where X(1)-X(4) were mixtures of selected amino acids and the flexible linker was 4-aminobutyric acid, also provided effective inhibition. Targeted PMLs containing the acidic amino acids Asp and Glu, the scissile-bond amino acids Gln and Arg and the zinc chelators His and Cys produced pronounced inhibition of BoNT-A. Deconvolution of these libraries will provide novel ligands with improved inhibitory potency as leads in the design of peptide mimetics to treat BoNT poisoning.
Hayden
J
J
Department of Pharmacology and Therapeutics, University of Calgary, Alberta T2N 1N4, Canada.
Pires
J
J
Roy
S
S
Hamilton
M
M
Moore
G J
GJ
D000992:Antitoxins; D001665:Binding Sites; D019274:Botulinum Toxins, Type A / Q000037:antagonists & inhibitors / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D015195:Drug Design; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000378:metabolism; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins
D000992:Antitoxins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D019151:Peptide Library; D010455:Peptides; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins; D019274:Botulinum Toxins, Type A