Yang Hui, Li Shihao, Li Fuhua, Xiang Jianhai
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Mar Drugs. 2016 May 19;14(5):96. doi: 10.3390/md14050096.
The lipopolysaccharide binding domain (LBD) in anti-lipopolysaccharide factor (ALF) is the main functional element of ALF, which exhibits antimicrobial activities. Our previous studies show that the peptide LBDv, synthesized based on the modified sequence of LBD (named LBD2) from FcALF2, exhibited an apparently enhanced antimicrobial activity. To learn the prospect of LBDv application, the characteristics of LBDv were analyzed in the present study. The LBDv peptide showed higher antimicrobial and bactericidal activities compared with LBD2. These activities of the LBDv peptide were stable after heat treatment. LBDv could also exhibit in vivo antimicrobial activity to Vibrio harveyi. The LBDv peptide was found to bind bacteria, quickly cause bacterial agglutination, and kill bacteria by damaging their membrane integrity. Structure analysis showed that both LBDv and LBD2 held the β-sheet structure, and the positive net charge and amphipathicity characteristic were speculated as two important components for their antimicrobial activity. The cytotoxicity of LBDv was evaluated in cultured Spodoptera frugiperda (Sf9) cells and Cherax quadricarinatus hemocytes. More than 80% cells could survive with the LBDv concentration up to 16 μM. Collectively, these findings highlighted the potential antimicrobial mechanism of LBD peptides, and provided important information for the commercial use of LBDv in the future.
抗脂多糖因子（ALF）中的脂多糖结合结构域（LBD）是ALF的主要功能元件，具有抗菌活性。我们之前的研究表明，基于来自FcALF2的LBD（命名为LBD2）的修饰序列合成的肽LBDv表现出明显增强的抗菌活性。为了解LBDv的应用前景，本研究分析了LBDv的特性。与LBD2相比，LBDv肽表现出更高的抗菌和杀菌活性。LBDv肽的这些活性在热处理后很稳定。LBDv对哈维氏弧菌也具有体内抗菌活性。发现LBDv肽能结合细菌，迅速引起细菌凝集，并通过破坏细菌的膜完整性来杀死细菌。结构分析表明，LBDv和LBD2都具有β-折叠结构，推测正净电荷和两亲性特征是它们抗菌活性的两个重要组成部分。在培养的草地贪夜蛾（Sf9）细胞和红螯螯虾血细胞中评估了LBDv的细胞毒性。当LBDv浓度高达16μM时，超过80%的细胞能够存活。总的来说，这些发现突出了LBD肽潜在的抗菌机制，并为LBDv未来的商业应用提供了重要信息。
