From the Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou 215123, Jiangsu.
the Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming 650223, Yunnan.
J Biol Chem. 2019 May 10;294(19):7615-7631. doi: 10.1074/jbc.RA118.006968. Epub 2019 Mar 20.
Mycobacteriophages express various peptides/proteins to infect (). Particular attention has been paid to mycobacteriophage-derived endolysin proteins. We herein characterized a small mycobacteriophage-derived peptide designated AK15 with potent anti- activity. AK15 adopted cationic amphiphilic α-helical structure, and on the basis of this structure, we designed six isomers with increased hydrophobic moment by rearranging amino acid residues of the helix. We found that one of these isomers, AK15-6, exhibits enhanced anti-mycobacterial efficiency. Both AK15 and AK15-6 directly inhibited by trehalose 6,6'-dimycolate (TDM) binding and membrane disruption. They both exhibited bactericidal activity, cell selectivity, and synergistic effects with rifampicin, and neither induced drug resistance to They efficiently attenuated mycobacterial load in the lungs of -infected mice. We observed that lysine, arginine, tryptophan, and an α-helix are key structural requirements for their direct anti-mycobacterial action. Of note, they also exhibited immunomodulatory effects, including inhibition of proinflammatory response in TDM-stimulated or -infected murine bone marrow-derived macrophages (BMDMs) and -infected mice and induction of only a modest level of cytokine (tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6)) production in murine BMDMs and a T-cell cytokine (interferin-γ (IFN-γ) and TNF-α) response in murine lung and spleen. In summary, characterization of a small mycobacteriophage-derived peptide and its improved isomer revealed that both efficiently restrain infection via dual mycobactericidal-immunoregulatory activities. Our work provides clues for identifying small mycobacteriophage-derived anti-mycobacterial peptides and improving those that have cationic amphiphilic α-helices.
噬菌体表达各种肽/蛋白以感染 （）。特别关注的是噬菌体衍生的溶菌酶蛋白。本文描述了一种小的噬菌体衍生肽，命名为 AK15，具有强大的抗 （）活性。AK15 采用阳离子两亲性 α-螺旋结构，在此基础上，我们通过重排螺旋中的氨基酸残基设计了六个疏水性矩增加的异构体。我们发现其中一个异构体 AK15-6 表现出增强的抗分枝杆菌效率。AK15 和 AK15-6 均通过与海藻糖 6,6'-二(mycolate) (TDM) 结合和破坏细胞膜直接抑制 （）。它们均具有杀菌活性、细胞选择性，与利福平具有协同作用，且不诱导 （）对它们的耐药性。它们在 -感染小鼠的肺部中有效地减轻了分枝杆菌负荷。我们观察到赖氨酸、精氨酸、色氨酸和 α-螺旋是它们直接抗分枝杆菌作用的关键结构要求。值得注意的是，它们还表现出免疫调节作用，包括抑制 TDM 刺激或 -感染的小鼠骨髓来源的巨噬细胞 (BMDM) 中的促炎反应和 -感染小鼠中的细胞因子（肿瘤坏死因子 α (TNF-α) 和白细胞介素 6 (IL-6))产生，并在小鼠 BMDM 和 T 细胞细胞因子（干扰素-γ (IFN-γ) 和 TNF-α）反应中诱导适度水平的细胞因子产生。总之，对一种小的噬菌体衍生肽及其改进的异构体的表征表明，两者均通过双重杀菌-免疫调节活性有效地抑制 （）感染。我们的工作为识别具有阳离子两亲性 α-螺旋的小噬菌体衍生的抗分枝杆菌肽提供了线索，并为改进这些肽提供了线索。
