The "pre-assembled state" of magainin 2 lysine-linked dimer determines its enhanced antimicrobial activity
The "pre-assembled state" of magainin 2 lysine-linked dimer determines its enhanced antimicrobial activity
复制标题
DOI：
10.1016/j.colsurfb.2018.04.034
复制
发表时间：
2018-07-01
影响因子：
5.8
通讯作者：
Oliveira, Osvaldo N., Jr.
中科院分区：
文献类型：
--
作者：
Lorenzon, Esteban N.;Nobre, Thatyane M.;Oliveira, Osvaldo N., Jr.
抗菌肽 (AMP) 是传统抗生素的替代品，可对抗多重耐药细菌，且产生微生物耐药性的可能性较低。此类分子的设计需要了解其作用机制，特别是与细菌细胞膜的相互作用。在这项工作中，我们确定了与单体肽 magainin 2 (MG2) 相比，magainin 2 (MG2)(2)K 的 C 端赖氨酸二聚体对大肠杆菌具有更高活性的机制。用大肠杆菌脂质提取物制成的朗缪尔单层和囊泡用于解决肽-膜相互作用的两种可能状态，分别是“结合状态”和“孔状态”。 MG2和(MG2)(2)K在空气-水界面的脂质单层中的掺入导致表面压力等温线和偏振调制红外反射吸收(PM-IRRAS)光谱的轻微差异，因此活性的差异与结合状态无关。相比之下，在渗漏实验中观察到了很大的差异，其中（MG2）（2）K由于有效的孔形成而在更大程度上破坏了大的单层囊泡。还通过分子动力学 (MD) 模拟对 1-palmitoy1-2-oleoyl-sn-g/ycero-3-磷酸乙醇胺:1-palmitoy1-2-oleoyl-snglycero-3-磷酸甘油 (POPE:POPG) 制成的双层探讨了 MG2 和 (MG2)(2)K 的结合和渗透。 (MG2)(2)K 形成无序环形孔的浓度显着低于 MG2。总之，实验和计算模拟结果相结合表明，(MG2)(2)K二聚体的“预组装状态”导致分子数量减少，杀死大肠杆菌所需的时间更短。 (C) 2018 Elsevier B.V. 保留所有权利。
Antimicrobial peptides (AMPs) are alternatives to conventional antibiotics against multi-drug resistant bacteria with low potential for developing microbial resistance. The design of such molecules requires understanding of the mechanisms of action, particularly the interaction with bacteria cell membranes. In this work, we determine the mechanism responsible for the higher activity against Escherichia coil of the C-terminal lysine dimer of magainin 2, (MG2)(2)K, in comparison to the monomeric peptide magainin 2 (MG2). Langmuir monolayers and vesicles made with the E. coli lipid extract were used to address the two possible states for the peptide-membrane interaction, namely the "binding state" and "pore state", respectively. The incorporation of MG2 and (MG2)(2)K in lipid monolayers at the air-water interface caused slight differences in surface pressure isotherms and polarization-modulated infrared reflection absorption (PM-IRRAS) spectra, and therefore the difference in activity is not associated with the binding state. In contrast, large differences were observed in the leakage experiments where (MG2)(2)K was shown to disrupt the large unilamellar vesicles to a much higher extent owing to efficient pore formation. The binding and penetration of MG2 and (MG2)(2)K were also probed with molecular dynamics (MD) simulations for bilayers made with 1-palmitoy1-2-oleoyl-sn-g/ycero-3-phosphoethanolamine:1-palmitoy1-2-oleoyl-snglycero-3-phosphoglycerol (POPE:POPG). (MG2)(2)K forms disordered toroidal pores at a significant lower concentration than for MG2. In summary, the combination of experimental and computational simulation results indicated that the "pre-assembling state" of (MG2)(2)K dimer leads to a reduced number of molecules and shorter time being required to kill E. coli. (C) 2018 Elsevier B.V. All rights reserved.