Zhao C, Liaw L, Lee I H, Lehrer R I
Department of Medicine, Scetion of Molecular Host Defense, UCLA School of Medicine, Los Angeles, CA 90095-1690, USA.
FEBS Lett. 1997 Jun 30;410(2-3):490-2. doi: 10.1016/s0014-5793(97)00646-7.
Clavanins are a family of alpha-helical antimicrobial peptides found in hemocytes of the tunicate, Styela clava. We examined a cDNA library prepared from pharyngeal tissues of S. clava and sequenced 24 clones that encoded prepropeptides of Clavanins A, C, D or E. These sequences indicated that Clavanins are synthesized as 9.2 kDa prepropeptides which contain a 19-residue signal peptide, followed in turn by a highly polar 'pro' region (LEERKSEEEK) with five glutamic acid residues, the 23 residues of the mature Clavanin peptide, the glycine residue needed for its amidation and a 27-residue polar C-terminal extension that is removed in later processing. Although the signal sequence and anionic propiece of Clavanin precursors share features with corresponding regions in precursors of the certain frog peptides, including ranalexin, gaegurins, dermaseptins and deltorphins, their unique multipartite structure suggests that they are not actually homologues of these amphibian peptides.
海鞘素是在柄海鞘血细胞中发现的一类α-螺旋抗菌肽。我们检测了从柄海鞘咽组织制备的cDNA文库，并对24个编码海鞘素A、C、D或E前原肽的克隆进行了测序。这些序列表明，海鞘素作为9.2 kDa的前原肽合成，其中包含一个19个残基的信号肽，接着是一个具有五个谷氨酸残基的高度极性的“前”区域（LEERKSEEEK）、成熟海鞘素肽的23个残基、其酰胺化所需的甘氨酸残基以及一个在后续加工中被去除的27个残基的极性C末端延伸。尽管海鞘素前体的信号序列和阴离子前肽部分与某些蛙肽前体的相应区域具有共同特征，包括雨蛙肽、加古林、皮肤抗菌肽和强啡肽，但它们独特的多部分结构表明它们实际上并非这些两栖类肽的同源物。
