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多肽与膜结合过程对于包括抗菌肽抗菌在内的多种生命过程都是非常重要的.我们利用基于电子顺磁共振技术的方法以pH敏感的多肽LAH4为研究对象,在人工磷脂膜上研究了多肽与膜的相互作用.根据标记在多肽上的氮氧自由基谱图变化,我们研究了LAH4与不同磷脂膜结合的亲和力及动力学信息.研究发现LAH4与带负电的POPG的结合明显强于DMPC及POPC.此外,pH同样影响LAH4与膜结合的速率,酸性条件下明显增快的结合可能是LAH4酸性条件下抗菌活性增强的原因之一.本研究的结果和方法为后续在细胞上研究抗菌肽的与膜结合及穿膜过程提供了基础.“,”Peptide-membrane binding is vital for many biological events,including the bacteria combating by antimicrobial peptides.Using the pH sensitive LAH4 peptide as model,we employed a convenient electron paramagnetic resonance (EPR) method to study the peptide-membrane binding process in artificial phospholipid membranes.Based on spectral changes of the nitroxide radical labeled to the peptides,we characterized binding kinetics and affinity of peptides to different phospholipid membranes.The binding affinity of LAH4 towards POPG was more than an order of magnitude higher than those towards DMPC and POPC.The binding kinetics showed that LAH4 initially bound to POPG much more quickly than to DMPC and POPC.Additionally,pH also affected the binding kinetics in LAH4-membrane interactions,which helped explain the pH dependent antimicrobial activity of LAH4.The method might be further used to monitor the membrane binding/cell penetration ofantimicrobial peptide in living cells.