Kim C R, Lee Y H, Bang I S, Kim E S, Kang C S, Yun C Y, Lee I H
Department of Life Science, Hoseo University, Asan City, Choongnam-Do, South Korea.
Arch Insect Biochem Physiol. 2000 Dec;45(4):149-55. doi: 10.1002/1520-6327(200012)45:4<149::AID-ARCH2>3.0.CO;2-H.
We have characterized full-length cDNAs encoding two isoforms of agriusin, cecropin D-like antibacterial peptide, present in the hemolymph of the immunized Agrius convolvuli larvae. The cloned cDNAs of agriusins 1 and 2 contain 331 and 329 bp, respectively. The nucleotide sequencing of cDNAs showed that they encode 62 amino acids, whose mature portion was deduced to consist of 38 amino acid residues with over 94% sequence identity. In the sequence homology search, mature agriusin 1 showed over 86 and 71% amino acid sequence homology with bactericidin 4 from Manduca sexta and cecropin D from Hyalophora cecropia, respectively. Since it was demonstrated from the deduced amino acid sequences that the C-terminal residues of agriusins are followed by a Gly residue, two types of synthetic agriusin 1 (syn-agriusin 1 amide and acid) were prepared to verify if natural agriusin 1 is C-terminally amidated. From acid-urea PAGE and reversed phase HPLC profiles to compare two synthetic peptides, we could confirm that the C-terminal amino acid residue of natural agriusin 1, like several cecropins so far identified, is amidated. Finally, our antibacterial assay performed with two syn-agriusins 1 revealed that there is little difference between antibacterial activities of both peptides against Gram-positive and Gram-negative bacteria.
我们对编码牵牛抗菌肽（一种类似天蚕素D的抗菌肽）两种同工型的全长cDNA进行了表征，该抗菌肽存在于免疫的牵牛幼虫的血淋巴中。克隆的牵牛抗菌肽1和2的cDNA分别包含331和329个碱基对。cDNA的核苷酸测序表明，它们编码62个氨基酸，其成熟部分推断由38个氨基酸残基组成，序列同一性超过94%。在序列同源性搜索中，成熟的牵牛抗菌肽1与烟草天蛾的杀菌素4和天蚕的天蚕素D的氨基酸序列同源性分别超过86%和71%。由于从推导的氨基酸序列中证明牵牛抗菌肽的C末端残基后面跟着一个甘氨酸残基，因此制备了两种类型的合成牵牛抗菌肽1（合成牵牛抗菌肽1酰胺和酸），以验证天然牵牛抗菌肽1的C末端是否酰胺化。通过酸性尿素PAGE和反相HPLC图谱比较两种合成肽，我们可以确认天然牵牛抗菌肽1的C末端氨基酸残基与迄今为止鉴定的几种天蚕素一样，是酰胺化的。最后，我们用两种合成牵牛抗菌肽1进行的抗菌试验表明，两种肽对革兰氏阳性菌和革兰氏阴性菌的抗菌活性几乎没有差异。
