Jayaraman Seetharaman, Eswaramoorthy Subramaniam, Ahmed S Ashraf, Smith Leonard A, Swaminathan Subramanyam
Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Biochem Biophys Res Commun. 2005 Apr 29;330(1):97-103. doi: 10.1016/j.bbrc.2005.02.123.
Botulinum neurotoxins comprise seven distinct serotypes (A-G) produced by Clostridium botulinum. The crystal structure of the binding domain of the botulinum neurotoxin type B (BBHc) has been determined to 2A resolution. The overall structure of BBHc is well ordered and similar to that of the binding domain of the holotoxin. However, significant structural changes occur at what would be the interface of translocation and binding domains of the holotoxin. The loop 911-924 shows a maximum displacement of 14.8A at the farthest point. The N-terminal helix reorients and moves by 19.5A from its original position. BBHc is compared with the binding domain of the holotoxin of botulinum type A and B, and the tetanus C-fragment to characterize the heavy chain-carbohydrate interactions. The probable reasons for different binding affinity of botulinum and tetanus toxins are discussed.
肉毒杆菌神经毒素由肉毒梭菌产生的七种不同血清型（A - G）组成。已确定B型肉毒杆菌神经毒素结合结构域（BBHc）的晶体结构分辨率为2埃。BBHc的整体结构排列有序，与全毒素结合结构域的结构相似。然而，在全毒素的易位结构域和结合结构域的界面处发生了显著的结构变化。环911 - 924在最远点显示出最大位移14.8埃。N端螺旋重新定向并从其原始位置移动了19.5埃。将BBHc与A型和B型肉毒杆菌全毒素的结合结构域以及破伤风C片段进行比较，以表征重链与碳水化合物的相互作用。讨论了肉毒杆菌毒素和破伤风毒素结合亲和力不同的可能原因。
