DasGupta B R, Tepp W
Department of Food Microbiology & Toxicology, University of Wisconsin, Madison 53706.
Biochem Biophys Res Commun. 1993 Jan 29;190(2):470-4. doi: 10.1006/bbrc.1993.1071.
We demonstrate here for the first time a proteolytic activity of botulinum neurotoxin type E which is not expressed unless the single chain approximately 150 kDa neurotoxic protein is nicked into the dichain approximately 150 kDa neurotoxin. Actin was cleaved, in vitro, at multiple sites by the dichain neurotoxin and the N-terminal approximately 50 kDa light chain segment isolated from the dichain neurotoxin. The scissile peptide bonds of actin invariably contained Arg or Lys at the P1 site. Proteolytic activity of the isolated light chain and expression of this activity in the dichain form of the neurotoxin are consistent with the light chain's and the neurotoxin's intracellular actions--inhibition of neurotransmitter release.
我们首次在此证明了E型肉毒杆菌神经毒素的蛋白水解活性，这种活性只有在约150 kDa的单链神经毒性蛋白被切割成约150 kDa的双链神经毒素时才会表达。在体外，肌动蛋白被双链神经毒素和从双链神经毒素中分离出的N端约50 kDa轻链片段在多个位点切割。肌动蛋白的可裂解肽键在P1位点总是含有精氨酸或赖氨酸。分离出的轻链的蛋白水解活性以及这种活性在神经毒素双链形式中的表达与轻链和神经毒素的细胞内作用——抑制神经递质释放是一致的。
