The membrane-binding properties of a class A amphipathic peptide
The membrane-binding properties of a class A amphipathic peptide
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DOI：
10.1007/s00249-003-0332-9
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发表时间：
2004-04-01
影响因子：
2
通讯作者：
Aguilar, MI
中科院分区：
文献类型：
--
作者：
Mozsolits, H;Lee, TH;Aguilar, MI
用两种不同的固定化模型膜系统研究了A类两亲性肽（18D）的膜结合特性。第一个系统涉及使用表面等离子体共振（SPR）来研究18 D与二肉豆蔻酰磷脂酰胆碱（DMPC）和二肉豆蔻酰磷脂酰甘油（DMPG）的结合，这允许真实的时间监测肽结合。SPR实验表明18D与DMPG的结合比DMPC强，动力学分析表明这是由于更快的结合速率。第二个模型膜系统涉及固定化膜色谱法，其中18 D的结合DMPC或DMPG单层共价连接到二氧化硅颗粒进行了分析，通过洗脱色谱法。与磷脂酰胆碱（PC）单层相比，带负电荷的磷脂酰甘油（PG）单层也获得了更强的18 D结合亲和力，这与SPR结果一致。还观察到18D与固定化脂质单层的非线性结合行为，这表明肽在与固定化PC和PG配体结合时经历构象和取向变化。在两个单层上也观察到显着的谱带展宽，在PC表面上获得较大的带宽，表明与两性离子表面的结合和取向动力学较慢。logk'对甲醇百分比的依赖性也表明了双峰相互作用，其中在较高的温度和甲醇浓度下疏水力占主导地位，而在较低的温度下，静电力和其他极性力也对肽对脂质单层的亲和力做出了贡献。总体而言，这些结果表明，这两个脂质生物传感器的互补使用，允许疏水和静电力的作用，在肽膜相互作用进行研究，并深入了解与这些相互作用相关的动力学因素。
The membrane-binding properties of a class A amphipathic peptide (18D) were investigated using two different immobilized model membrane systems. The first system involved the use of surface plasmon resonance (SPR) to study the binding of 18D to dimyristylphosphatidylcholine (DMPC) and dimyristylphosphatidylglycerol (DMPG), which allowed peptide binding to be monitored in real time. The SPR experiments indicated stronger binding of 18D to DMPG than DMPC, which kinetic analysis revealed was due to a faster on-rate. The second model membrane system involved immobilized membrane chromatography in which the binding of 18D to either DMPC or DMPG monolayers covalently linked to silica particles was analysed by elution chromatography. Stronger binding affinity of 18D was also obtained with the negatively charged phosphatidylglycerol (PG) monolayer compared to the phosphatidylcholine (PC) monolayer, which was consistent with the SPR results. Non-linear binding behaviour of 18D to the immobilized lipid monolayers was also observed, which suggests that the peptide undergoes conformational and orientational changes upon binding to the immobilized PC and PG ligands. Significant band broadening was also observed on both monolayers, with larger bandwidths obtained on the PC surface, indicating slower binding and orientation kinetics with the zwitterionic surface. The dependence of logk' on the percentage of methanol also demonstrated a bimodal interaction whereby hydrophobic forces predominated at higher temperatures and methanol concentrations, while at lower temperatures, electrostatic and other polar forces also made a contribution to the affinity of the peptides for the lipid monolayer particularly. Overall, these results demonstrate the complementary use of these two lipid biosensors which allows the role of hydrophobic and electrostatic forces in peptide-membrane interactions to be studied and insight gained into the kinetic factors associated with these interactions.