Effect of deuteration on lipid monolayer phase behaviour as a function of temperature

A biological cell membrane is based on a bilayer of lipid molecules, which form a selective barrier in which functional molecules are embedded. The nature of the lipid constituents is important for the action of these molecules and our research aims to link lipid structure with the properties of the monolayers and bilayers they form. Studies of model systems often employ isotopic labelling to separate signals from different constituents in the model. Deuterium labelling is used in spectroscopic and neutron studies on the assumption that the chemical and physical behaviour of the molecules is unchanged. In this study, we propose to determine the conditions in which the assumption is valid and those in which it is not, using x-rays (which are insensitive to isotopic substitution) as the probe to compare structure of deuterated and undeuterated lipid monolayers at different temperatures. This experiment was conceived as part of a joint Diamond-ISIS proposal, which was awarded by Diamond. The Diamond portion of the experiment has been successfully carried out and here we request time to carry out the neutron reflectivity component of the experiment.

生物细胞膜以脂质分子双层为基础，该双层构成了嵌入功能性分子的选择性屏障。脂质组分的性质对这些分子的作用至关重要，我们的研究旨在将脂质结构与其形成的单分子层和双层的性质联系起来。模型系统的研究常采用同位素标记（isotopic labelling）来分离模型中不同组分的信号。氘标记（Deuterium labelling）用于光谱学和中子研究，其假设是分子的化学和物理行为保持不变。在本研究中，我们拟利用对同位素取代（isotopic substitution）不敏感的X射线作为探针，比较不同温度下氘代和非氘代脂质单分子层的结构，以确定该假设成立与不成立的条件。本实验是Diamond-ISIS联合提案的一部分，该提案由Diamond资助。实验的Diamond部分已成功完成，在此我们申请时间开展实验的中子反射率部分。