Division of Biophysics, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany.
Biophys Chem. 2010 Aug;150(1-3):80-7. doi: 10.1016/j.bpc.2010.01.009. Epub 2010 Jan 29.
An analysis of the interaction of the NK-lysin derived peptide NK-2 and of analogs thereof with bacterial lipopolysaccharide (LPS, endotoxin) was performed to determine the most important biophysical parameters for an effective LPS neutralization. We used microcalorimetry, FTIR spectroscopy, Zeta potential measurements, and small-angle X-ray scattering to analyze the peptide:LPS binding enthalpy, the accessible LPS surface charge, the fluidity of the LPS hydrocarbon chains, their phase transition enthalpy change, the aggregate structure of LPS, and how these parameters are modulated by the peptides. We conclude that (i) a high peptide:LPS binding affinity, which is facilitated by electrostatic and hydrophobic interactions and which leads to a positive Zeta potential, (ii) the formation of peptide-enriched domains, which destabilize the lipid packing, demonstrated by a drastic decrease of phase transition enthalpy change of LPS, and (iii) the multilamellarization of the LPS aggregate structure are crucial for an effective endotoxin neutralization by cationic peptides.
对 NK-溶素衍生肽 NK-2 及其类似物与细菌脂多糖 (LPS，内毒素) 的相互作用进行了分析，以确定有效中和 LPS 的最重要的生物物理参数。我们使用微量量热法、傅里叶变换红外光谱、Zeta 电位测量和小角 X 射线散射来分析肽：LPS 结合焓、可及 LPS 表面电荷、LPS 烃链流动性、相变焓变化、LPS 的聚集结构以及这些参数如何被肽调节。我们得出结论，(i) 高肽：LPS 结合亲和力，这是由静电和疏水相互作用促进的，导致正 Zeta 电位，(ii) 肽富集域的形成，通过 LPS 相变焓变化的急剧下降，破坏了脂质的堆积，(iii) LPS 聚集结构的多层化对于阳离子肽有效中和内毒素至关重要。
