Luchini Alessandra, Sebastiani Federica, Tidemand Frederik Grønbæk, Batchu Krishna Chaithanya, Campana Mario, Fragneto Giovanna, Cárdenas Marité, Arleth Lise
Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
Biofilms Research Center for Biointerfaces and Department of Biomedical Science, Faculty of Health and Society, Malmö University, Per Albin Hanssons Väg 35, 21432 Malmö, Sweden.
J Colloid Interface Sci. 2021 Mar;585:376-385. doi: 10.1016/j.jcis.2020.11.086. Epub 2020 Nov 26.
Supported lipid bilayers (SLBs) are commonly used to investigate the structure and dynamics of biological membranes. Vesicle fusion is a widely exploited method to produce SLBs. However, this process becomes less favoured when the vesicles contain complex lipid mixtures, e.g. natural lipid extracts. In these cases, it is often necessary to change experimental parameters, such as temperature, to unphysiological values to trigger the SLB formation. This may induce lipid degradation and is also not compatible with including membrane proteins or other biomolecules into the bilayers. Here, we show that the peptide discs, ~10 nm discoidal lipid bilayers stabilized in solution by a self-assembled 18A peptide belt, can be used as precursors for SLBs. The characterizations by means of neutron reflectometry and attenuated total reflectance-FTIR spectroscopy show that SLBs were successfully formed both from synthetic lipid mixtures (surface coverage 90-95%) and from natural lipid mixtures (surface coverage ~85%). Traces of 18A peptide (below 0.02 M ratio) left at the support surface after the bilayer formation do not affect the SLB structure. Altogether, we demonstrate that peptide disc formation of SLBs is much faster than the SLB formation by vesicle fusion and without the need of altering any experimental variable from physiologically relevant values.
支持脂质双层（SLB）常用于研究生物膜的结构和动力学。囊泡融合是一种广泛应用于制备SLB的方法。然而，当囊泡含有复杂的脂质混合物，如天然脂质提取物时，这个过程就不太容易实现。在这些情况下，通常需要将实验参数，如温度，改变到非生理值来触发SLB的形成。这可能会导致脂质降解，并且也不适合将膜蛋白或其他生物分子包含在双层中。在这里，我们表明，肽盘，即由自组装的18A肽带在溶液中稳定的约10纳米盘状脂质双层，可以用作SLB的前体。通过中子反射率和衰减全反射傅里叶变换红外光谱进行的表征表明，SLB可以成功地由合成脂质混合物（表面覆盖率90-95%）和天然脂质混合物（表面覆盖率约85%）形成。双层形成后留在支持表面的痕量18A肽（比例低于0.02 M）不会影响SLB的结构。总之，我们证明，通过肽盘形成SLB比通过囊泡融合形成SLB要快得多，并且不需要从生理相关值改变任何实验变量。
