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Title: Fluorescence cross-correlation spectroscopy of lipid-peptide interactions on supported lipid bilayers
Electrostatic interactions drive molecular assembly and organization in the plasma membrane. Specific protein-lipid interactions, however, are difficult to resolve. Here we report on a unique approach to investigate these interactions with time-resolved fluorescence spectroscopy. The experiments were performed on a model membrane system consisting of a supported lipid bilayer with an asymmetric distribution of PIP2 in the upper leaflet of the bilayer. The bilayer also contained nickel-chelating lipids that bind to a histidine-tagged peptide of interest. Both the peptide and the lipid were labeled with orthogonal fluorescent probes, so that diffusion and binding could be measured with two-color, pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). Our PIE-FCCS data showed significant lipid-peptide cross-correlation between PIP2 lipids and membrane-bound cationic peptides. Cross-correlation is a direct indication of lipid-peptide binding and complexation. Together with mobility data, we quantified the degree of binding, which offers new insight into this class of lipid-peptide interactions. Overall, this is the first report of lipid-peptide cross-correlation by FCCS, and provides a new route to quantifying the interactions between proteins and lipid membranes, a key interface in cell signaling.  more » « less
Award ID(s):
1753060
NSF-PAR ID:
10095394
Author(s) / Creator(s):
Date Published:
Journal Name:
Advances in biomembranes and lipid self-assembly
Volume:
29
ISSN:
2451-9626
Page Range / eLocation ID:
49 - 68
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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