Characterization of a chimeric antimicrobial peptide uncovers evolutionary significance of exon-shuffling.
Characterization of a chimeric antimicrobial peptide uncovers evolutionary significance of exon-shuffling.
复制标题
DOI：
10.1016/j.bbrc.2012.10.059
复制
发表时间：
2012-11
影响因子：
3.1
通讯作者：
K. Zhu;B. Gao;Shunyi Zhu
中科院分区：
文献类型：
--
作者：
K. Zhu;B. Gao;Shunyi Zhu
阿巴霉素家族由一类富含脯氨酸的抗菌肽 (AMP) 组成，在膜翅目昆虫中分布有限。有趣的是，在寄生黄蜂 Nasonia vitripennis 中，其成员（称为 nabaecin-1 至 -3）通过外显子改组获得了富含羧基末端甘氨酸的抗菌单元。在这里，我们描述了nabaecin-3和改组的供体基因（navitripenicin）的cDNA克隆，以及nabaecin-3及其两个结构域（分别称为氨基末端阿巴霉素单元（NtAU）和羧基末端navitripenicin单元（CtNU））的结构和功能特征。发现 Nabaecin-3 和 navitripenicin 在应对细菌挑战时转录上调。通过重组表达和化学合成技术，我们生产了nabaecin-3、NtAU和CtNU。圆二色性 (CD) 分析表明这些肽的结构显着不同。从功能上讲，nabaecin-3 在微摩尔浓度下对一系列细菌、酵母和真菌表现出广泛的抗菌活性，而 CtNU 仅具有微弱的抗菌活性，而 NtAU 完全缺乏活性。我们的结果表明，在 Nasonia 中，阿巴霉素的抗菌功能取决于 NtAU 与 CtNU 的组合，因此表明外显子改组在缓冲基因功能丧失突变中的新作用。
The abaecin family comprises a class of proline-rich antimicrobial peptides (AMPs) with restricted distribution in hymenopteran insects. Intriguingly, in the parasitic wasp Nasonia vitripennis its members (termed nabaecin-1 to -3) have gained a carboxyl terminal glycine-rich antimicrobial unit through exon-shuffling. Here, we describe cDNA cloning of nabaecin-3 and the donor gene (navitripenicin) of the shuffling, and structural and functional features of nabaecin-3 and its two domains (respectively called amino-terminal abaecin unit (NtAU) and carboxyl-terminal navitripenicin unit (CtNU)). Nabaecin-3 and navitripenicin were found to be transcriptionally up-regulated in response to bacterial challenge. By using recombinant expression and chemical synthesis techniques, we produced nabaecin-3, NtAU and CtNU. Circular dichroism (CD) analyses show that these peptides remarkably differ in their structures. Functionally, nabaecin-3 displayed a wide spectrum of antimicrobial activity against an array of bacteria, yeasts and fungi at micromolar concentrations, while CtNU only had a weak antibacterial activity and NtAU completely lacked activity. Our results indicate that in Nasonia the antimicrobial function of abaecin depends on the combination of NtAU with CtNU and thus suggest a new role of exon-shuffling in buffering loss-of-function mutation of a gene.