de Souza Amanda Neves, Cardoso Gabriele de Azevedo, Nunes Lúcio Otávio, Aisenbrey Christopher, Salnikov Evgeniy, de Souza Kelton Rodrigues, Saad Ahmad, de Lima Maria Elena, Resende Jarbas Magalhães, Bechinger Burkhard, Verly Rodrigo Moreira
Departamento de Química, Faculdade de Ciências Exatas, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Campus JK, Diamantina 39100-000, MG, Brazil.
Institut de Chimie, Université de Strasbourg, CNRS, UMR7177, 67000 Strasbourg, France.
Antibiotics (Basel). 2025 Jan 10;14(1):66. doi: 10.3390/antibiotics14010066.
This study investigates the structural and biophysical properties of the wild-type antimicrobial peptide LyeTx I, isolated from the venom of the spider , and its analog LyeTx I-b, designed to enhance antibacterial activity, selectivity, and membrane interactions by the acetylation and increased amphipathicty. : To understand the mechanisms behind these enhanced properties, comparative analyses of the structural, topological, biophysical, and thermodynamic aspects of the interactions between each peptide and phospholipid bilayers were evaluated. Both peptides were isotopically labeled with H-Ala and N-Leu to facilitate structural studies via NMR spectroscopy. Circular dichroism and solid-state NMR analyses revealed that, while both peptides adopt α-helical conformations in membrane mimetic environments, LyeTx I-b exhibits a more amphipathic and extended helical structure, which correlates with its enhanced membrane interaction. The thermodynamic properties of the peptide-membrane interactions were quantitatively evaluated in the presence of phospholipid bilayers using ITC and DSC, highlighting a greater propensity of LyeTx I-b to disrupt lipid vesicles. Calcein release studies reveal that both peptides cause vesicle disruption, although DLS measurements and TEM imaging indicate distinct effects on phospholipid vesicle organization. While LyeTx I-b permeabilizes anionic membrane retaining the vesicle integrity, LyeTx I promotes significant vesicle agglutination. Furthermore, DSC and calcein release assays indicate that LyeTx I-b exhibits significantly lower cytotoxicity toward eukaryotic membranes compared to LyeTx I, suggesting greater selectivity for bacterial membranes. : Our findings provide insights into the structural and functional modifications that enhance the antimicrobial and therapeutic potential of LyeTx I-b, offering valuable guidance for the design of novel peptides targeting resistant bacterial infections and cancer.
本研究调查了从蜘蛛毒液中分离出的野生型抗菌肽LyeTx I及其类似物LyeTx I-b的结构和生物物理性质。LyeTx I-b通过乙酰化和增加两亲性来增强抗菌活性、选择性和膜相互作用。为了理解这些增强特性背后的机制，对每种肽与磷脂双层之间相互作用的结构、拓扑、生物物理和热力学方面进行了比较分析。两种肽都用H-Ala和N-Leu进行了同位素标记，以便通过核磁共振光谱进行结构研究。圆二色性和固态核磁共振分析表明，虽然两种肽在模拟膜环境中都采用α-螺旋构象，但LyeTx I-b表现出更具两亲性和延伸的螺旋结构，这与其增强的膜相互作用相关。使用等温滴定量热法（ITC）和差示扫描量热法（DSC）在磷脂双层存在下定量评估了肽-膜相互作用的热力学性质，突出了LyeTx I-b对破坏脂质囊泡的更大倾向。钙黄绿素释放研究表明，两种肽都能引起囊泡破坏，尽管动态光散射（DLS）测量和透射电子显微镜（TEM）成像表明对磷脂囊泡组织有不同影响。虽然LyeTx I-b使阴离子膜通透并保持囊泡完整性，但LyeTx I促进显著的囊泡凝集。此外，DSC和钙黄绿素释放测定表明，与LyeTx I相比，LyeTx I-b对真核膜的细胞毒性显著降低，表明对细菌膜具有更高的选择性。我们的研究结果为增强LyeTx I-b的抗菌和治疗潜力的结构和功能修饰提供了见解，为设计针对耐药细菌感染和癌症的新型肽提供了有价值的指导。
