Thanabalu T, Porter A G
Institute of Molecular and Cell Biology, National University of Singapore, Republic of Singapore.
Gene. 1996 Apr 17;170(1):85-9. doi: 10.1016/0378-1119(95)00836-5.
A size-fractionated genomic library of Bacillus sphaericus strain SSII-1 was constructed and screened for toxicity against larvae of the mosquito Culex quinquefasciatus (Cq). One toxin-producing clone, pS35, was identified and a 2.7-kb subclone was completely sequenced. An open reading frame of 879 bp encoding a 31.8-kDa protein (designated Mtx2) was identified. Purified, recombinant Mtx2 was toxic to Cq larvae. Mtx2 shows no significant homology to known insecticidal toxins, but has homology to two toxins active against mammalian cells, namely the epsilon-toxin of Clostridium perfringens and the cytotoxin of Pseudomonas aeruginosa. Thus, Mtx2 represents a new type of mosquitocidal toxin.
构建了球形芽孢杆菌SSII-1菌株的一个按大小分级的基因组文库，并筛选其对致倦库蚊（Cq）幼虫的毒性。鉴定出一个产毒素克隆pS35，并对一个2.7kb的亚克隆进行了全序列测定。鉴定出一个879bp的开放阅读框，其编码一个31.8kDa的蛋白质（命名为Mtx2）。纯化的重组Mtx2对Cq幼虫有毒性。Mtx2与已知的杀虫毒素没有显著同源性，但与两种对哺乳动物细胞有活性的毒素有同源性，即产气荚膜梭菌的ε毒素和铜绿假单胞菌的细胞毒素。因此，Mtx2代表一种新型的杀蚊毒素。
