Oizumi Yuki, Hemmi Hikaru, Minami Masayoshi, Asaoka Ai, Yamakawa Minoru
Biotechnology Research Center, Kubota Corporation, Ryugasaki, Ibaraki 301-0852, Japan.
Biochim Biophys Acta. 2005 Aug 31;1752(1):83-92. doi: 10.1016/j.bbapap.2005.07.013.
An antibacterial peptide was isolated from a lepidopteran insect, Spodoptera litura. The molecular mass of this peptide was determined to be 4489.55 by matrix assisted laser desorption/ionization-time of flight mass (MALDI-TOF MS) spectrometry. The peptide consists of 42 amino acids and the sequence has 69-98% identity to those of moricin-related peptides, antibacterial peptides from lepidopetran insects. Thus, the peptide was designated S. litura (Sl) moricin. Sl moricin showed a broad antibacterial spectrum against Gram-positive and negative bacteria. Sl moricin gene was inducible by bacterial injection and expressed tissue-specifically in the fat body and hemocytes. Furthermore, the solution structure of Sl moricin was determined by two-dimensional (2D) 1H-nuclear magnetic resonance (NMR) spectroscopy and hybrid distance geometry-simulated annealing calculation. The tertiary structure revealed a long alpha-helix containing eight turns along nearly the full length of the peptide like that of moricin, confirming that Sl moricin is a new moricin-like antibacterial peptide. These results suggest that moricin is present not only in B. mori but also in other lepidopteran insects forming a gene family.
从鳞翅目昆虫斜纹夜蛾中分离出一种抗菌肽。通过基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）测定，该肽的分子量为4489.55。该肽由42个氨基酸组成，其序列与来自鳞翅目昆虫的桑蚕抗菌肽（moricin）相关肽的序列具有69-98%的同一性。因此，该肽被命名为斜纹夜蛾（Sl）桑蚕抗菌肽。Sl桑蚕抗菌肽对革兰氏阳性和阴性细菌均表现出广谱抗菌活性。Sl桑蚕抗菌肽基因可通过细菌注射诱导，并在脂肪体和血细胞中特异性表达。此外，通过二维（2D）1H-核磁共振（NMR）光谱和混合距离几何模拟退火计算确定了Sl桑蚕抗菌肽的溶液结构。三级结构显示，与桑蚕抗菌肽一样，该肽沿几乎整个肽长度包含八个螺旋圈的长α-螺旋，证实Sl桑蚕抗菌肽是一种新的类桑蚕抗菌肽。这些结果表明，桑蚕抗菌肽不仅存在于家蚕中，也存在于其他形成基因家族的鳞翅目昆虫中。
