Guo Jiubiao, Chan Edward Wai Chi, Chen Sheng
Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, PR China; State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Shenzhen Key Lab for Food Biological Safety Control, Food Safety and Technology Research Center, Hong Kong PolyU Shen Zhen Research Institute, Shenzhen, PR China; State Key Lab of Chirosciences, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Toxicon. 2016 Mar 1;111:77-85. doi: 10.1016/j.toxicon.2015.12.020. Epub 2015 Dec 31.
BoNT/F7, one of the seven subtypes of botulinum neurotoxin type F (F1 to F7), is the second-most divergent subtype of this group. Despite sharing >60% identity with BoNT/F1 at both holotoxin and enzymatic domain levels, it requires an N-terminal extended peptide substrate for efficient substrate cleavage, suggesting its unique substrate recognition and specificity mechanism. Substrate mapping and saturation mutagenesis analysis revealed that VAMP2 (20-65) was likely a minimally effective substrate for LC/F7 (light chain of BoNT/F7), and in addition, LC/F7 recognized VAMP2 in a unique way, which differed significantly from that of LC/F1, although both of them share similar substrate binding and hydrolysis mode. LC/F7 utilizes distinct pockets for specific substrate binding and recognition in particular for the B1, B2 and S2 sites recognitions. Our findings provide insights into the distinct substrate recognition features of BoNT subtypes and useful information for therapy development for BoNT/F.
肉毒杆菌神经毒素F型（F1至F7）的七个亚型之一BoNT/F7，是该组中第二差异最大的亚型。尽管在全毒素和酶结构域水平上与BoNT/F1的同源性>60%，但它需要一个N端延伸肽底物才能有效切割底物，这表明其具有独特的底物识别和特异性机制。底物图谱和饱和诱变分析表明，VAMP2（20-65）可能是LC/F7（BoNT/F7的轻链）的最小有效底物，此外，LC/F7以独特的方式识别VAMP2，这与LC/F1有显著差异，尽管它们具有相似的底物结合和水解模式。LC/F7利用不同的口袋进行特定底物的结合和识别，特别是对于B1、B2和S2位点的识别。我们的研究结果为了解BoNT亚型独特的底物识别特征提供了见解，并为BoNT/F的治疗开发提供了有用信息。
