Yang G H, Rhee S D, Jung H H, Jhee O H, Yang K H
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Yusong, Taejon, Korea.
Biochem Mol Biol Int. 1998 Jun;45(2):401-7. doi: 10.1080/15216549800202782.
The upstream region of the gene coding for Clostridium botulinum type B (BoNT/B) neurotoxin was cloned and sequenced. There were two open reading frames, which were identified as a nontoxic-nonhemagglutinin component (ntnh/B) and a 22 kDa adjacent open reading frame (orf22/B). Deduced primary structure of ntnh/B showed that it was composed of 1,197 amino acid residues. Pairwise comparisons of the ntnh/B component with other botulinum toxin types showed high degree of homology to ntnh/A (82% identity). Northern blot analysis revealed that toxin gene could be transcribed alone or co-transcribed with the ntnh gene. The orf22/B gene encoding for 178 amino acids (M.W. 21.6 kDa) was located between the 33 kDa hemagglutinin gene and the ntnh gene. Orf22/B also showed high degree of homology to orf22/A (98.9% identity). These results suggested that the upstream region of the BoNT/B gene (containing the ntnh/B and orf22/B genes) might be evolutionarily closely related to the counterparts of the BoNT/A.
对编码肉毒杆菌B型（BoNT/B）神经毒素的基因上游区域进行了克隆和测序。存在两个开放阅读框，分别被鉴定为无毒-无血凝素成分（ntnh/B）和一个22 kDa相邻开放阅读框（orf22/B）。ntnh/B推导的一级结构显示它由1197个氨基酸残基组成。ntnh/B成分与其他肉毒杆菌毒素类型的成对比较显示与ntnh/A具有高度同源性（82%同一性）。Northern印迹分析表明毒素基因可以单独转录或与ntnh基因共转录。编码178个氨基酸（分子量21.6 kDa）的orf22/B基因位于33 kDa血凝素基因和ntnh基因之间。Orf22/B也与orf22/A具有高度同源性（98.9%同一性）。这些结果表明BoNT/B基因的上游区域（包含ntnh/B和orf22/B基因）可能在进化上与BoNT/A的对应区域密切相关。
