Brevinin-1BYa is a 24-amino acid residue host-defense peptide, first isolated from skin secretions of the foothill yellow-legged frog Rana boylii. The peptide is of interest, as it shows broad-spectrum antimicrobial activity, and is particularly effective against opportunistic yeast pathogens. Its potential for clinical use, however, is hindered by its latent haemolytic activity. The structures of two analogues, the less haemolytic [C18S,C24S]brevinin-1BYa and the more potent cis-dicarba-brevinin-1BYa, were investigated in various solution and membrane-mimicking environments by [Formula: see text] spectroscopy and molecular modelling techniques. Neither peptide possesses a secondary structure in aqueous solution. In both the membrane-mimicking sodium dodecyl sulphate micelles and 33% 2,2,2-trifluoroethanol ([Formula: see text] solvent mixture, the peptides' structures are characterised by two [Formula: see text]-helices connected by a flexible hinge located at the [Formula: see text] residues. With the aid of molecular dynamics simulations and paramagnetic probes, it was determined that the peptides' helical segments lie parallel to the micellar surface, with their hydrophobic residues facing towards the micelle core and the hydrophilic residues pointing outwards, suggesting that both peptides exert their biological activity by a non-pore-forming mechanism. Unlike that of the dicarba analogue, the C-terminus of the acyclic peptide is only weakly associated with the micellar surface and is in direct contact with the surrounding aqueous solvent.

中文翻译：

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深入了解无环和双氨基桥联的brevinin-1BYa抗菌肽的构象和膜相互作用。

Brevinin-1BYa是一种24氨基酸残基的宿主防御肽，首先从山麓黄脚蛙Rana boylii的皮肤分泌物中分离出来。该肽是令人感兴趣的，因为它显示出广谱的抗菌活性，并且对机会性酵母病原体特别有效。然而，其潜在的溶血活性阻碍了其在临床上的应用潜力。通过[分子式：光谱]和各种分子模型，在各种溶液和膜模拟环境中研究了两种类似物的结构，即溶血性较低的[C18S，C24S] brevinin-1BYa和更有效的顺式-dicarba-brevinin-1BYa。技术。两种肽在水溶液中都不具有二级结构。在模仿膜的十二烷基硫酸钠胶束和33％2,2,2-三氟乙醇（[配方：参见文字]溶剂混合物中，肽的结构以两个[分子式]螺旋为特征，两个螺旋通过位于[分子式]残基的柔性铰链连接。借助分子动力学模拟和顺磁性探针，已确定该肽的螺旋节段平行于胶束表面，其疏水性残基面向胶束核心，亲水性残基朝外，表明这两种肽均发挥了其生物学作用。通过非孔形成机制的活性。与双卡巴类似物不同，无环肽的C末端仅与胶束表面弱结合，并与周围的水性溶剂直接接触。见文字]残留物。借助分子动力学模拟和顺磁性探针，已确定该肽的螺旋节段平行于胶束表面，其疏水性残基面向胶束核心，亲水性残基朝外，表明这两种肽均发挥了其生物学作用。通过非孔形成机制的活性。与双卡巴类似物不同，无环肽的C末端仅与胶束表面弱结合，并与周围的水性溶剂直接接触。见文字]残留物。借助分子动力学模拟和顺磁性探针，已确定该肽的螺旋节段平行于胶束表面，其疏水性残基面向胶束核心，亲水性残基朝外，表明这两种肽均发挥了其生物学作用。通过非孔形成机制的活性。与双卡巴类似物不同，无环肽的C末端仅与胶束表面弱结合，并与周围的水性溶剂直接接触。其疏水性残基面向胶束核心，亲水性残基朝外，表明这两种肽均通过非孔形成机制发挥其生物学活性。与双卡巴类似物不同，无环肽的C末端仅与胶束表面弱结合，并与周围的水性溶剂直接接触。其疏水性残基面向胶束核心，亲水性残基朝外，表明这两种肽均通过非孔形成机制发挥其生物学活性。与双卡巴类似物不同，无环肽的C末端仅与胶束表面弱结合，并与周围的水性溶剂直接接触。