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首页> 外文期刊>Biochemistry >Fourier transform infrared spectroscopic studies of the interaction of the antimicrobial peptide gramicidin S with lipid micelles and with lipid monolayer and bilayer membranes.
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Fourier transform infrared spectroscopic studies of the interaction of the antimicrobial peptide gramicidin S with lipid micelles and with lipid monolayer and bilayer membranes.

机译：傅里叶变换红外光谱研究抗菌肽短杆菌肽S与脂质微团以及脂质单层和双层膜的相互作用。

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摘要

We have utilized Fourier transform infrared spectroscopy to study the interaction of the antimicrobial peptide gramicidin S (GS) with lipid micelles and with lipid monolayer and bilayer membranes as a function of temperature and of the phase state of the lipid. Since the conformation of GS does not change under the experimental conditions employed in this study, we could utilize the dependence of the frequency of the amide I band of the central beta-sheet region of this peptide on the polarity and hydrogen-bonding potential of its environment to probe GS interaction with and location in these lipid model membrane systems. We find that the GS is completely or partially excluded from the gel states of all of the lipid bilayers examined in this study but strongly partitions into lipid micelles, monolayers, or bilayers in the liquid-crystalline state. Moreover, in general, the penetration of GS into zwitterionic and uncharged lipid bilayer coincides closely with the gel to liquid-crystalline phase transition of the lipid. However, GS begins to penetrate into the gel-state bilayers of anionic phospholipids prior to the actual chain-melting phase transition, while in cationic lipid bilayers, GS does not partition strongly into the liquid-crystalline bilayer until temperatures well above the chain-melting phase transition are reached. In the liquid-crystalline state, the polarity of the environment of GS indicates that this peptide is located primarily at the polar/apolar interfacial region of the bilayer near the glycerol backbone region of the lipid molecule. However, the depth of GS penetration into this interfacial region can vary somewhat depending on the structure and charge of the lipid molecule. In general, GS associates most strongly with and penetrates most deeply into more disordered bilayers with a negative surface charge, although the detailed chemical structure of the lipid molecule and physical organization of the lipid aggregate (micelle versus monolayer versus bilayer) also have minor effects on these processes.
机译：我们已经利用傅里叶变换红外光谱来研究抗微生物肽短杆菌肽S（GS）与脂质微团以及与脂质单层和双层膜的相互作用，该作用是温度和脂质相态的函数。由于GS的构象在本研究中使用的实验条件下不会改变，因此我们可以利用该肽的中心β-折叠区域的酰胺I谱带的频率对其肽的极性和氢键电势的​​依赖性环境，以探测GS与这些脂质模型膜系统的相互作用以及在这些脂质模型膜系统中的位置。我们发现，本研究中检查的所有脂质双层的凝胶状态都完全或部分排除了GS，但在液晶状态下它们强烈地分成脂质胶束，单层或双层。此外，通常，GS渗透到两性离子和不带电荷的脂质双层中，与脂质从凝胶到液晶的相变非常吻合。但是，GS在实际的链熔化相变之前就开始渗透到阴离子磷脂的凝胶态双层中，而在阳离子脂质双层中，GS直到温度远高于链熔化温度时才牢固地分配到液晶双层中达到相变。在液晶状态下，GS环境的极性指示该肽主要位于双层的极性/非极性界面区域，靠近脂质分子的甘油主链区域。但是，GS渗入该界面区域的深度可能会有所不同，具体取决于脂质分子的结构和电荷。通常，尽管脂质分子的详细化学结构和脂质聚集体的物理组织（胶束，单层或双层）对GS的影响最弱，但GS与最混乱的双层最紧密地结合并最深地渗透到更混乱的双层中。这些过程。

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