Atomic Recombination in Dynamic Secondary Ion Mass Spectrometry Probes Distance in Lipid Assemblies: A Nanometer Chemical Ruler.
Atomic Recombination in Dynamic Secondary Ion Mass Spectrometry Probes Distance in Lipid Assemblies: A Nanometer Chemical Ruler.
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DOI：
10.1021/jacs.6b10655
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发表时间：
2016-12-28
影响因子：
15
通讯作者：
Boxer SG
中科院分区：
文献类型：
--
作者：
Moss FR 3rd;Boxer SG
生物膜的横向组织被认为发生在纳米长度尺度上。然而，这种长度尺度以及小脂质和蛋白质结构域的动态性质使得生物膜和模型系统中的这种组织的表征变得困难。在这里，我们介绍一种使用稳定同位素标记测量单层和双层中脂质共定位的新方法。我们利用动态 SIMS 中发生的一个称为原子重组的过程，其中不同分子上的原子结合形成双原子离子，并用 NanoSIMS 仪器进行检测。这个过程对分子之间的距离高度敏感。通过测量不同脂质分子上 13C 和 15N 原子形成 13C15N− 离子的效率，我们测量了双层横向组织的变化，即使这些异质性发生在仅几纳米的长度范围内，远低于 NanoSIMS 仪器或什至最好的超分辨率荧光方法的初级离子束的直径。使用这种技术，我们为模型膜中的纳米级相分离提供了直接证据，这可能为生物膜的组织提供比具有微米级相分离的脂质混合物更好的模型。我们期望这项技术能够广泛适用于化学和生物系统中感兴趣或未知的非常短尺度接近的任何组装。
The lateral organization of biological membranes is thought to take place on the nanometer length scale. However, this length scale and the dynamic nature of small lipid and protein domains have made characterization of such organization in biological membranes and model systems difficult. Here we introduce a new method for measuring the colocalization of lipids in monolayers and bilayers using stable isotope labeling. We take advantage of a process that occurs in dynamic SIMS called atomic recombination, in which atoms on different molecules combine to form diatomic ions that are detected with a NanoSIMS instrument. This process is highly sensitive to the distance between molecules. By measuring the efficiency of the formation of 13C15N− ions from 13C and 15N atoms on different lipid molecules, we measure variations in the lateral organization of bilayers even though these heterogeneities occur on a length scale of only a few nm, well below the diameter of the primary ion beam of the NanoSIMS instrument or even the best super-resolution fluorescence methods. Using this technique, we provide direct evidence for nanoscale phase separation in a model membrane, which may provide a better model for the organization of biological membranes than lipid mixtures with microscale phase separation. We expect this technique to be broadly applicable to any assembly where very short scale proximity is of interest or unknown, both in chemical and biological systems.