PDF(Pubmed)
Abstract：
Rattusin, an α-defensin-related antimicrobial peptide isolated from the small intestine of rats, has been previously characterized through NMR spectroscopy to elucidate its three-dimensional structure, revealing a C2 homodimeric scaffold stabilized by five disulfide bonds. This study aimed to identify the functional region of rattusin by designing and synthesizing various short analogs, subsequently leading to the development of novel peptide-based antibiotics. The analogs, designated as F1, F2, F3, and F4, were constructed based on the three-dimensional configuration of rattusin, among which F2 is the shortest peptide and exhibited superior antimicrobial efficacy compared to the wild-type peptide. The central cysteine residue of F2 prompted an investigation into its potential to form a dimer at neutral pH, which is critical for its antimicrobial function. This activity was abolished upon the substitution of the cysteine residue with serine, indicating the necessity of dimerization for antimicrobial action. Further, we synthesized β-hairpin-like analogs, both parallel and antiparallel, based on the dimeric structure of F2, which maintained comparable antimicrobial potency. In contrast to rattusin, which acts by disrupting bacterial membranes, the F2 dimer binds directly to DNA, as evidenced by fluorescence assays and DNA retardation experiments. Importantly, F2 exhibited negligible cytotoxicity up to 515 μg/mL, assessed via hemolysis and MTT assays, underscoring its potential as a lead compound for novel peptide-based antibiotic development.
摘要：
Rattusin,从大鼠小肠分离的α-防御素相关抗菌肽，先前已通过NMR光谱表征以阐明其三维结构，揭示了由五个二硫键稳定的C2同源二聚体支架。本研究旨在通过设计和合成各种短的类似物来识别rattusin的功能区域。随后导致新型基于肽的抗生素的开发。类似物，标记为F1，F2，F3和F4，是基于rattusin的三维结构而构建的，其中F2是最短的肽,并且与野生型肽相比表现出优异的抗微生物效力。F2的中央半胱氨酸残基促使研究其在中性pH下形成二聚体的潜力，这对其抗菌功能至关重要。这种活性在半胱氨酸残基被丝氨酸取代后被取消，表明二聚化对抗菌作用的必要性。Further,我们合成了β-发夹样类似物，平行和反平行，基于F2的二聚体结构,其保持相当的抗微生物效力。与rattusin相比，通过破坏细菌膜起作用，F2二聚体直接与DNA结合,荧光测定和DNA延迟实验证明了这一点。重要的是,F2表现出可忽略的细胞毒性，高达515μg/mL，通过溶血和MTT测定进行评估，强调其作为新型基于肽的抗生素开发的先导化合物的潜力。
