Kalb Suzanne R, Baudys Jakub, Smith Theresa J, Smith Leonard A, Barr John R
Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy, NE, Atlanta, GA 30341, USA.
Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Ft. Detrick, MD 21702, USA.
Toxins (Basel). 2017 Jun 15;9(6):193. doi: 10.3390/toxins9060193.
Botulism is a disease involving intoxication with botulinum neurotoxins (BoNTs), toxic proteins produced by and other clostridia. The 150 kDa neurotoxin is produced in conjunction with other proteins to form the botulinum progenitor toxin complex (PTC), alternating in size from 300 kDa to 500 kDa. These progenitor complexes can be classified into hemagglutinin positive or hemagglutinin negative, depending on the ability of some of the neurotoxin-associated proteins (NAPs) to cause hemagglutination. The hemagglutinin positive progenitor toxin complex consists of BoNT, nontoxic non-hemagglutinin (NTNH), and three hemagglutinin proteins; HA-70, HA-33, and HA-17. Hemagglutinin negative progenitor toxin complexes contain BoNT and NTNH as the minimally functional PTC (M-PTC), but not the three hemagglutinin proteins. Interestingly, the genome of hemagglutinin negative progenitor toxin complexes comprises open reading frames (orfs) which encode for three proteins, but the existence of these proteins has not yet been extensively demonstrated. In this work, we demonstrate that these three proteins exist and form part of the PTC for hemagglutinin negative complexes. Several hemagglutinin negative strains producing BoNT/A, /E, and /F were found to contain the three open reading frame proteins. Additionally, several BoNT/A-containing bivalent strains were examined, and NAPs from both genes, including the open reading frame proteins, were associated with BoNT/A. The open reading frame encoded proteins are more easily removed from the botulinum complex than the hemagglutinin proteins, but are present in several BoNT/A and /F toxin preparations. These are not easily removed from the BoNT/E complex, however, and are present even in commercially-available purified BoNT/E complex.
肉毒中毒是一种由肉毒杆菌神经毒素（BoNTs）中毒引起的疾病，肉毒杆菌神经毒素是由肉毒杆菌及其他梭菌产生的有毒蛋白质。150 kDa的神经毒素与其他蛋白质结合产生，形成肉毒杆菌祖毒素复合物（PTC），大小在300 kDa至500 kDa之间交替变化。这些祖毒素复合物可根据一些神经毒素相关蛋白（NAPs）引起血凝的能力分为血凝素阳性或血凝素阴性。血凝素阳性祖毒素复合物由BoNT、无毒非血凝素（NTNH）和三种血凝素蛋白组成；HA-70、HA-33和HA-17。血凝素阴性祖毒素复合物含有BoNT和NTNH作为最小功能PTC（M-PTC），但不包含三种血凝素蛋白。有趣的是，血凝素阴性祖毒素复合物的基因组包含编码三种蛋白质的开放阅读框（orfs），但这些蛋白质的存在尚未得到广泛证实。在这项研究中，我们证明这三种蛋白质存在，并构成血凝素阴性复合物PTC的一部分。发现几种产生BoNT/A、/E和/F的血凝素阴性菌株含有这三种开放阅读框蛋白。此外，还检测了几种含BoNT/A的二价菌株，来自两个基因的NAPs，包括开放阅读框蛋白，都与BoNT/A相关。与血凝素蛋白相比，开放阅读框编码的蛋白更容易从肉毒杆菌复合物中去除，但存在于几种BoNT/A和/F毒素制剂中。然而，这些蛋白不容易从BoNT/E复合物中去除，甚至存在于市售的纯化BoNT/E复合物中。
