Juliano Samuel A, Pierce Scott, deMayo James A, Balunas Marcy J, Angeles-Boza Alfredo M
Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
Division of Medicinal Chemistry, Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
Biochemistry. 2017 Mar 14;56(10):1403-1414. doi: 10.1021/acs.biochem.6b01046. Epub 2017 Mar 3.
Tunicates have been used as primitive models for understanding cell-mediated and humoral immunity. Clavanin A (ClavA) is one member of a family of antimicrobial peptides produced by the solitary tunicate Styela clava. In this work, we demonstrate that ClavA utilizes Zn ions to potentiate its antimicrobial activity not only by reducing the concentration at which the peptide inhibits the growth of bacteria but also by increasing the rate of killing. Membrane depolarization, β-galactosidase leakage, and potassium leakage assays indicate that ClavA is membrane active, forms small pores, but induces cell death by targeting an intracellular component. ClavA and ClavA-Zn added to Escherichia coli and imaged by confocal microscopy translocate across the cell membrane. E. coli mutants lacking the functional Zn import system are less susceptible to ClavA, suggesting that the synergistic activity between ClavA and Zn has a cytoplasmic target, which is further supported by its nucleolytic activity. Overall, these studies identify a remarkable new mechanism by which zinc contributes to the immune response in the tunicate S. clava.
被囊动物已被用作理解细胞介导免疫和体液免疫的原始模型。Clavanin A（ClavA）是独居被囊动物柄海鞘产生的抗菌肽家族的一员。在这项工作中，我们证明ClavA利用锌离子增强其抗菌活性，这不仅是通过降低该肽抑制细菌生长的浓度，还通过提高杀伤速率来实现的。膜去极化、β-半乳糖苷酶泄漏和钾离子泄漏试验表明，ClavA具有膜活性，能形成小孔，但通过靶向细胞内成分诱导细胞死亡。添加到大肠杆菌中的ClavA和ClavA-Zn通过共聚焦显微镜成像显示可跨细胞膜转运。缺乏功能性锌导入系统的大肠杆菌突变体对ClavA的敏感性较低，这表明ClavA与锌之间的协同活性有一个细胞质靶点，其核酸酶活性进一步支持了这一点。总体而言，这些研究确定了一种显著的新机制，通过该机制锌有助于柄海鞘的免疫反应。
