Hemilä H, Glode L M, Palva I
Genesit Ltd., Helsinki, Finland.
FEMS Microbiol Lett. 1989 Nov;53(1-2):193-8. doi: 10.1111/j.1574-6968.1989.tb03621.x.
The gene coding for a nontoxic diphtheria toxin (DT), tox228, was isolated from lysogenic Corynebacterium diphtheriae and cloned into pBR322. A mature form of the tox228 gene, lacking its signal sequence, was expressed in Bacillus subtilis using a B. amyloliquefaciens alpha-amylase secretion vector. To test the possibility of producing partially deleted DT molecules, which could be used for cell-directed toxin conjugates, a truncated form lacking 151 amino acids from the C-terminus of the DT was generated by oligonucleotide mutagenesis. Both the truncated and intact DT were efficiently secreted into the culture medium. During prolonged cultivation, the truncated form was less stable than the intact DT molecule.
编码无毒白喉毒素（DT）的基因tox228，从溶源性白喉棒状杆菌中分离出来并克隆到pBR322中。使用解淀粉芽孢杆菌α-淀粉酶分泌载体，在枯草芽孢杆菌中表达了缺失信号序列的成熟形式的tox228基因。为了测试生产可用于细胞定向毒素偶联物的部分缺失DT分子的可能性，通过寡核苷酸诱变产生了一种从DT的C末端缺失151个氨基酸的截短形式。截短的DT和完整的DT都有效地分泌到培养基中。在长时间培养过程中，截短形式比完整的DT分子更不稳定。
