Suzuki Tomonori, Yoneyama Tohru, Miyata Keita, Mikami Akifumi, Chikai Tomoyuki, Inui Ken, Kouguchi Hirokazu, Niwa Koichi, Watanabe Toshihiro, Miyazaki Satoru, Ohyama Tohru
Department of Medicinal and Life Science, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510, Japan.
Biochem Biophys Res Commun. 2009 Feb 6;379(2):309-13. doi: 10.1016/j.bbrc.2008.12.050. Epub 2008 Dec 25.
A protease was purified from the culture medium of Clostridium botulinum serotype C strain Stockholm (C-St). The purified protease belonged to the cysteine protease family based on assays for enzyme inhibitors, activators and kinetic parameters. The protease formed a binary complex consisting of 41- and 17-kDa proteins held together non-covalently. The DNA sequence encoding the protease gene was shown to be a single open reading frame of 1593 nucleotides, predicting 530 amino acid residues including a signal peptide. The N-terminal region of the native enzyme underwent further proteolytic modification after processing by a signal peptidase. The protease introduced intermolecular cleavage into an intact single chain botulinum neurotoxin (BoNT) at a specific site. Homology modeling and docking simulation of C-St BoNT and C-St protease demonstrated that the specific nicking-site of the BoNT appears to fit into the deep pocket in the active site of the protease.
从肉毒梭菌C型斯德哥尔摩菌株（C-St）的培养基中纯化出一种蛋白酶。基于对酶抑制剂、激活剂和动力学参数的测定，纯化的蛋白酶属于半胱氨酸蛋白酶家族。该蛋白酶形成了一种由41 kDa和17 kDa蛋白质通过非共价键结合在一起的二元复合物。编码该蛋白酶基因的DNA序列显示为一个1593个核苷酸的单一开放阅读框，预测有530个氨基酸残基，包括一个信号肽。天然酶的N端区域在信号肽酶处理后经历了进一步的蛋白水解修饰。该蛋白酶在特定位点对完整的单链肉毒杆菌神经毒素（BoNT）进行分子间切割。C-St BoNT和C-St蛋白酶的同源性建模和对接模拟表明，BoNT的特定切割位点似乎适合蛋白酶活性位点的深口袋。
