Protein-membrane interaction: insights from advanced microscopy

Abstract

The interaction between proteins and membranes is sub ject of renewed interest in biomedical and biotechnologi cal research for its implication in many functional and dys functional processes and for its pharmaceutical applications. It has been shown that the interaction between amyloido genic proteins and membranes results in mutually destruc tive structural perturbations. The study we present is focused on the interaction between synthetic model membranes and alpha-lactalbumin (α-La), widely studied for its biolog ical function since it can induce apoptosis in tumor cells. Upon α-La addition to giant vesicles (GVs) samples, the sys tem has been characterized by means of spectroscopy meth ods and advanced microscopy techniques. Using Raster Image Correlation Spectroscopy (RICS) and Fluorescence Life time Imaging Microscopy (FLIM), the interaction has been investigated at different protein:lipid ratios. Starting from the molten globule conformation, a quick insertion of α-La into the lipid bilayer takes place, with evident changes in GVs morphology as well as in protein structure. The pro cess, ruled by a combination of electrostatic and hydrophobic interactions, ends with the formation of heterogeneous struc tures containing both protein and lipids. Eur Biophys J (2017) 46 (Suppl 1):S43–S402 S351 12