Using Fluorine Nuclear Magnetic Resonance To Probe the Interaction of Membrane-Active Peptides with the Lipid Bilayer
Using Fluorine Nuclear Magnetic Resonance To Probe the Interaction of Membrane-Active Peptides with the Lipid Bilayer
复制标题
DOI：
10.1021/bi100605e
复制
发表时间：
2010-07-13
期刊：
影响因子：
2.9
通讯作者：
Marsh, E. Neil G.
中科院分区：
文献类型：
--
作者：
Buer, Benjamin C.;Chugh, Jeetender;Marsh, E. Neil G.
多种生物活性肽通过与细胞的脂质膜直接相互作用来发挥其功能。这些表面相互作用通常是短暂的和高度动态的，使它们难以研究。在这里，我们研究了使用溶液相F-19核磁共振（NMR）研究肽膜相互作用的可行性。使用的抗菌肽MSI-78作为一个模型系统，我们表明，肽结合到小的单层囊泡（SUV）或bicelles可以很容易地检测到简单的一维F-19 NMR实验与标记的肽与L-4，4，4-三氟乙基甘氨酸。与肽-膜复合物相关的化学位移对三氟甲基报告基团的位置（无论是在两亲性肽的疏水面还是带正电荷的面中）和脂质双层的曲率（无论肽是结合到SUV还是bicelles）都敏感。使用Carr-Purcell-Meiboom-Gill脉冲序列的F-19自旋回波实验用于测量核的横向弛豫（T-2），从而检查结合到双胞的MSI-78类似物的局部迁移率。位于肽的疏水面的氟探针以与双胞的翻滚相关的速率松弛，表明它相对不动，而带正电的面的探针松弛得更慢，表明该位置更具动态性。这些结果与MSI-78与脂质结合的结构模型雅阁，并指出使用氟标记肽来监测活细胞中肽-膜相互作用的可行性。
A variety of biologically active peptides exert their function through direct interactions with the lipid membrane of the cell. These surface interactions are generally transient and highly dynamic, making them hard to study. Here we have examined the feasibility of using solution phase F-19 nuclear magnetic resonance (NMR) to study peptide membrane interactions. Using the antimicrobial peptide MSI-78 as a model system, we demonstrate that peptide binding to either small unilamellar vesicles (SUVs) or bicelles can readily be detected by simple one-dimensional F-19 NMR experiments with peptides labeled with L-4,4,4-trifluoroethylglycine. The chemical shift associated with the peptide-membrane complex is sensitive both to the position of the trifluoromethyl reporter group (whether in the hydrophobic face or positively charged face of the amphipathic peptide) and to the curvature of the lipid bilayer (whether the peptide is bound to SUVs or bicelles). F-19 spin echo experiments using the Carr-Purcell-Meiboom-Gill pulse sequence were used to measure the transverse relaxation (T-2) of the nucleus and thereby examine the local mobility of the MSI-78 analogues bound to bicelles. The fluorine probe positioned in the hydrophobic face of the peptide relaxes at a rate that correlates with the tumbling of the bicelle, suggesting that it is relatively immobile, whereas the probe at the positively charged face relaxes more slowly, indicating this position is much more dynamic. These results are in accord with structural models of MSI-78 bound to lipids and point to the feasibility of using fluorine-labeled peptides to monitor peptide-membrane interactions in living cells.