Department of Microbiology, University of Stockholm, S-106 91 Stockholm, Sweden.
EMBO J. 1984 Sep;3(9):2071-5. doi: 10.1002/j.1460-2075.1984.tb02093.x.
The Cecropia moth has three known classes of antibacterial immune proteins, attacins, lysozyme and cecropins (earlier referred to as P5, P7 and P9, respectively). Six attacins with different isoelectric points have been purified. The N-terminal sequences for five of these forms imply that only two different genes exist. We have now isolated and sequenced two cDNA clones, one for the basic attacin and one for the acidic form. The two mature proteins show 76% homology at the nucleotide level, while the regions beyond the stop codons are 36% homologous. The differences in the content of aspartic acid accounts for the difference in net charge between the acidic and basic attacin. Further differences in charge can be obtained by post-translational removal of a lysine-containing tetrapeptide at the C-terminal end of the two proteins. Evidence for a prepro form of the basic attacin is presented.
大蚕蛾属的昆虫有三种已知的抗菌免疫蛋白，分别为 attacins、溶菌酶和 cecropins（以前分别称为 P5、P7 和 P9）。已经纯化了六种等电点不同的 attacins。其中五种形式的 N 端序列表明只存在两种不同的基因。我们现在已经分离并测序了两个 cDNA 克隆，一个是碱性 attacin，另一个是酸性形式。两种成熟蛋白在核苷酸水平上显示出 76%的同源性，而在终止密码子之后的区域则有 36%的同源性。天冬氨酸含量的差异导致酸性和碱性 attacin 之间的净电荷差异。通过在两种蛋白质的 C 末端去除一个赖氨酸四肽，可以获得进一步的电荷差异。碱性 attacin 的前原形式的证据被提出。
