Data from: How Peptide Molecular Structure and Charge Influence the Nanostructure of Lipid Bicontinuous Cubic Mesophases: Model Synthetic WALP Peptides Provide Insights

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Nanostructured bicontinuous lipidic cubic phases are used for the encapsulation of proteins in a range of applications such as in meso crystallization of trans membrane proteins and as drug delivery vehicles. The retention of the nanoscale order of the cubic phases subsequent to protein incorporation, as well as retention of the protein structure and function, is essential for all of these applications. Herein synthetic peptides (WALP21, WALPS53, and WALPS73) with a common a-helical hydrophobic domain, but varying hydrophilic loop size, were designed to systematically examine the effect of peptide structure and charge on bicontinuous cubic phases. The effect of the cubic phases on the secondary structure of the peptides was also investigated. The incorporation of the WALP peptides in cubic phases formed by a range of lipids showed that hydrophobic mismatch of the peptides with the lipid bilayers, the hydrophilic domain size, and peptide charge were all significant factors determining the response of the lipid nanomaterial to protein insertion. As charge repulsion had the most significant effect on the phase transitions observed, we suggest that buffer pH and salt concentration must be carefully considered to ensure cubic mesophase retention. Importantly, the WALP peptides were found to have a different conformation depending on the local lipid environment. Such structural changes could potentially affect membrane protein function, which is crucial for both current and prospective applications.

本附件文件为关联文章提供补充数据集。纳米结构双连续脂质立方相（nanostructured bicontinuous lipidic cubic phases）可用于蛋白质包封，应用场景涵盖跨膜蛋白（transmembrane proteins）的脂中结晶（in meso crystallization）以及作为药物递送载体等诸多领域。在蛋白质掺入后，该立方相仍能维持其纳米尺度有序性，同时保持蛋白质的结构与功能，这对于上述所有应用均至关重要。本研究设计了具有共同α-螺旋疏水结构域（α-helical hydrophobic domain）、但亲水环尺寸各异的合成肽（WALP21、WALPS53及WALPS73），以系统探究肽的结构与电荷对双连续脂质立方相的影响。同时本研究还探究了该立方相对肽二级结构的影响。对多种脂质形成的立方相中掺入WALP肽的研究表明，肽与脂质双层（lipid bilayers）间的疏水错配（hydrophobic mismatch）、亲水结构域尺寸以及肽电荷，均是决定该脂质纳米材料（lipid nanomaterial）对蛋白质插入响应的关键因素。鉴于电荷排斥（charge repulsion）对所观测到的相变影响最为显著，因此我们建议需谨慎调控缓冲液pH与盐浓度，以确保立方中间相（cubic mesophase）的稳定性保留。值得注意的是，研究发现WALP肽的构象（conformation）会随局部脂质环境的不同而发生改变。此类结构变化或可影响膜蛋白的功能，这对于当前及未来的相关应用均具有关键意义。