Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.69 (botulinum neurotoxin)
 1,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Torpedo electric organ has been used to study the binding of botulinum neurotoxin type A to pure cholinergic synaptosomes and presynaptic plasma membrane. 125I-labeled botulinum neurotoxin type A exhibits specific binding to cholinergic fractions. Two binding sites have been determined according to data analysis: a high affinity binding site (synaptosomes: Kd = 0.11 +/- 0.03 nM, Bmax = 50 +/- 10 fmol.mg prot-1; presynaptic plasma membrane: Kd = 0.2 +/- 0.05 nM, Bmax = 150 +/- 15 fmol.mg prot-1) and a low affinity binding site (synaptosomes: Kd approximately 26 nM, Bmax approximately 7.5 pmol.mg prot-1; presynaptic plasma membrane: Kd approximately 30 nM, Bmax approximately 52 pmol.mg prot-1). The binding of 125I-botulinum neurotoxin type A is decreased by previous treatment of synaptosomes by neuraminidase and trypsin, and by a preincubation with bovine brain gangliosides or antiserum raised against Torpedo presynaptic plasma membrane. When presynaptic plasma membranes are blotted to nitrocellulose sheet, either 125I-botulinum neurotoxin or botulinum toxin-gold complexes bind to a M(r) approximately 140,000 protein. Botulinum toxin-gold complexes have also been used to study the toxin internalization process into Torpedo synaptosomes. The images fit the three step sequence model in the pathway of botulinum neurotoxin poisoning.
J Neural Transm Gen Sect 1992
PMID:Binding of botulinum neurotoxin to pure cholinergic nerve terminals isolated from the electric organ of Torpedo. 133 17

A 12.3 kb DNA fragment encompassing the botulinum neurotoxin C1 (BoNT/C1) gene and an upstream flanking region was sequenced from Clostridium botulinum C 468 phage 1C. The resulting bont/C1 locus includes six genes which are organized into three transcriptional units. Cluster 1 encompasses the bont/C1 gene and an upstream gene encoding a non-toxic protein associated with the toxin (Antp139/C1). Transcriptional analysis revealed that these two genes form an operon; the bont/C1 gene can be transcribed alone or co-transcribed with antp139/C1. Cluster 2 encompasses three genes (antp33/C1, antp17/C1 and antp70/C1), which also form an operon. The corresponding proteins are similar to components of the hemagglutinin complex associated with BoNT/A and BoNT/B of C. botulinum A and B. In addition, Antp33/C1 is identical to HA-33, an hemagglutinin encoded by C. botulinum C-Stockholm phage C-St; Antp70/C1 displays some relatedness to C. perfringens enterotoxin. The third transcriptional unit consists of orf-22, which encodes a basic protein showing 29% identity with the gene product of uviA, a plasmid-encoded protein of 22 kDa which has been identified as a positive regulator of the bacteriocin production in C. perfringens. Orf-22 could be an effector controlling the expression of the bont/C1 and its antp genes in C. botulinum C 468.
Mol Gen Genet 1994 Jun 15
PMID:Organization of the botulinum neurotoxin C1 gene and its associated non-toxic protein genes in Clostridium botulinum C 468. 802 79

Native Clostridium botulinum gene coding for type A neurotoxin has been used to construct recombinant derivatives coding separately for L and H polypeptide chains of the toxin. The gene derivatives have been cloned into an expression vector pET28b in E. coli BL21 (DE3) cells. The recombinant L and H proteins seem to be the major individual proteins after IPTG induction of the recombinant cells. Each of the proteins has been accumulated only in inclusion bodies. The recombinant L chain (but not H chain) has been successfully resolubilized. Each of the proteins contains six His residues on the N terminus which allows purification on Ni-agarose columns with high yield. No toxic effect has been observed for both L and H chains after injection of 10 micrograms of recombinant preparations purified from inclusion bodies. Moreover, the injection resulted in an increase in the titer of specific antibodies which protected mice from 1 DLM of type A native botulinum neurotoxin. Hence, the recombinant neurotoxin protein derivatives which are present in E. coli inclusion bodies can be a source of material for producing diagnostic and therapeutic sera against type A botulinum neurotoxin.
Mol Gen Mikrobiol Virusol 2000
PMID:[Effective expression of fragments of a botulinum neurotoxin type A gene, coding for the L-chain and H-chain in E. coli, with formation of products causing protective immunity to administration of the toxin]. 1118 57