Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal.
Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília 71966-700, Brazil.
Int J Mol Sci. 2020 Nov 30;21(23):9104. doi: 10.3390/ijms21239104.
Discovering antibiotic molecules able to hold the growing spread of antimicrobial resistance is one of the most urgent endeavors that public health must tackle. The case of Gram-negative bacterial pathogens is of special concern, as they are intrinsically resistant to many antibiotics, due to an outer membrane that constitutes an effective permeability barrier. Antimicrobial peptides (AMPs) have been pointed out as potential alternatives to conventional antibiotics, as their main mechanism of action is membrane disruption, arguably less prone to elicit resistance in pathogens. Here, we investigate the in vitro activity and selectivity of EcDBS1R4, a bioinspired AMP. To this purpose, we have used bacterial cells and model membrane systems mimicking both the inner and the outer membranes of , and a variety of optical spectroscopic methodologies. EcDBS1R4 is effective against the Gram-negative , ineffective against the Gram-positive and noncytotoxic for human cells. EcDBS1R4 does not form stable pores in , as the peptide does not dissipate its membrane potential, suggesting an unusual mechanism of action. Interestingly, EcDBS1R4 promotes a hemi-fusion of vesicles mimicking the inner membrane of . This fusogenic ability of EcDBS1R4 requires the presence of phospholipids with a negative curvature and a negative charge. This finding suggests that EcDBS1R4 promotes a large lipid spatial reorganization able to reshape membrane curvature, with interesting biological implications herein discussed.
发现能够遏制抗菌药物耐药性不断蔓延的抗生素分子是公共卫生必须应对的最紧迫任务之一。革兰氏阴性细菌病原体的情况尤其令人担忧，因为它们由于存在外膜而对许多抗生素具有天然抗性，外膜构成了有效的渗透屏障。抗菌肽 (AMP) 已被指出是传统抗生素的潜在替代品，因为它们的主要作用机制是破坏细胞膜，据称不太容易在病原体中引发耐药性。在这里，我们研究了生物灵感 AMP EcDBS1R4 的体外活性和选择性。为此，我们使用细菌细胞和模拟内外膜的模型膜系统，以及各种光学光谱方法。EcDBS1R4 对革兰氏阴性 有效，对革兰氏阳性 无效，对人细胞无细胞毒性。EcDBS1R4 不会在 中形成稳定的孔，因为肽不会耗散其膜电位，这表明其作用机制不同寻常。有趣的是，EcDBS1R4 促进了模拟内膜的囊泡的半融合。EcDBS1R4 的这种融合能力需要具有负曲率和负电荷的磷脂的存在。这一发现表明，EcDBS1R4 促进了能够重塑膜曲率的大脂质空间重排，在此讨论了其中的有趣生物学意义。
