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Differential endopeptidase activity of different forms of type A botulinum neurotoxin: A unique relationship between the size of the substrate and activity of the enzyme
- Source :
- Toxicon. 144:34-41
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- Botulinum neurotoxins (BoNTs; serotypes A-G) are metalloproteases, which cleave and inactivate cellular proteins essential for neurotransmitter release. In bacterial cultures, BoNTs are secreted as a complex of the neurotoxin and a group of neurotoxin associated proteins (NAPs). Under physiological condition (pH 7.4), this complex is believed to be dissociated to separate the neurotoxin from NAPs. BoNT consists of a 50 kDa light (L) chain (LC or catalytic domain) and a 100 kDa heavy (H) chain (or HC) linked through a disulfide bond and other non-covalent interactions. The cell intoxication involves three major steps; binding, membrane translocation and inhibition of neurotransmitter release. The last step of intoxication, endopeptidase activity, is very unique and specific that can be used for detection of the complex and isolated forms of the toxin. A fluorescent tag-labeled synthetic peptide (SNAPtide) derived from a segment of SNAP-25, an intracellular substrate of BoNT/A, is used to detect and assay the endopeptidase activity of BoNT/A. The detection of the signal is based on the change in the fluorescence energy transfer after selective cleavage of the peptide by the BoNT/A. In this report, we demonstrate that SNAPtide as a commonly used substrate widely differ in reaction with BoNT/A complex, BoNT/A, and BoNT/A light chain. These findings have implications for assays used in detection, and in screening potential inhibitors.
- Subjects :
- 0301 basic medicine
Synaptosomal-Associated Protein 25
Neurotoxins
Peptide
Toxicology
medicine.disease_cause
Immunoglobulin light chain
03 medical and health sciences
Endopeptidase activity
Protein Domains
Catalytic Domain
Endopeptidases
Clostridium botulinum
Fluorescence Resonance Energy Transfer
medicine
Neurotoxin
Disulfides
Botulinum Toxins, Type A
chemistry.chemical_classification
030102 biochemistry & molecular biology
Toxin
030104 developmental biology
Enzyme
Biochemistry
chemistry
Intracellular
Subjects
Details
- ISSN :
- 00410101
- Volume :
- 144
- Database :
- OpenAIRE
- Journal :
- Toxicon
- Accession number :
- edsair.doi.dedup.....b550df97e52614c1ff68382efcc159a5