School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
J Microbiol Biotechnol. 2013 Oct 28;23(10):1386-94. doi: 10.4014/jmb.1306.06012.
In our previous study, the 25-mer antimicrobial peptide pleurocidin (Ple) had been thought to induce apoptosis in Candida albicans. This study demonstrated that reactive oxygen species (ROS) production was a major cause of Ple-induced apoptosis. Four truncated analogs were synthesized to understand the functional roles in the N- and C-terminal regions of Ple on the apoptosis. Ple, Ple (4-25), Ple (1-22), and Ple (1-19) produced ROS, including hydroxyl radicals, on the order of [Ple > Ple (1-22) > Ple (4-25) > Ple (1-19)], whereas Ple (7-25) did not induce any ROS production. The results suggested that the N-terminal deletion affected the ROS-inducing activities much more than that of the C-terminal deletion, and net hydrophobicity [Ple > Ple (1-22) > Ple (4-25) > Ple (1-19) > Ple (7-25)] was related to ROS generation rather than other primary factors like net charge. Hence, we focused on the N-terminal-truncated peptides, Ple (4-25) and Ple (7-25), and examined other apoptotic features, including mitochondrial membrane depolarization, caspase activation, phosphatidylserine externalization, and DNA and nuclear fragmentation. The results also confirmed the disappearance of apoptotic activity of Ple (7-25) by the truncation of the N-terminal region (1-6) and the specific activity patterns between Ple and analogs. In conclusion, the N-terminal region of Ple played an important role in apoptosis.
在我们之前的研究中，25 肽抗菌肽 pleurocidin（Ple）被认为能诱导白色念珠菌细胞凋亡。本研究表明，活性氧（ROS）的产生是 Ple 诱导凋亡的主要原因。合成了四个截断类似物，以了解 Ple 的 N 端和 C 端区域在凋亡中的功能作用。Ple、Ple（4-25）、Ple（1-22）和 Ple（1-19）均能产生 ROS，包括羟自由基，其产生顺序为 [Ple > Ple（1-22）> Ple（4-25）> Ple（1-19）]，而 Ple（7-25）则不能诱导任何 ROS 产生。结果表明，N 端缺失比 C 端缺失更能影响 ROS 的诱导活性，净疏水性 [Ple > Ple（1-22）> Ple（4-25）> Ple（1-19）> Ple（7-25）]与 ROS 的产生有关，而不是净电荷等其他主要因素。因此，我们集中研究了 N 端截断的肽 Ple（4-25）和 Ple（7-25），并检测了其他凋亡特征，包括线粒体膜去极化、半胱天冬酶激活、磷脂酰丝氨酸外翻以及 DNA 和核片段化。结果还证实了通过截断 N 端区域（1-6），Ple（7-25）缺失 N 端后其凋亡活性的消失，以及 Ple 及其类似物之间的特定活性模式。总之，Ple 的 N 端区域在凋亡中起着重要作用。
