Biophysical Society Conference | Tahoe 2022

Molecular Biophysics of Membranes

Poster Abstracts

5-POS Board 2 BICELLE SEGREGATION MEASURED AS A FUNCTION OF COMPOSITION- DEPENDENT VARIATIONS

Christopher P. Baryiames ; Matthew Necelis 1 ; Linda Columbus 1 ; 1 The University of Virginina, Chemistry, Charlottesville, VA, USA

Despite being essential for understanding the structure and function of cells and proteins, the energetics of specific lipid-lipid interactions remain elusive. This is in part due to the extreme heterogeneity of the lipid bilayer, which contains thousands of lipid species, necessitating the use of membrane models. Bicelles are attractive options for membrane studies as they combine the small scattering profile of micelles with the bilayer-like environment of vesicles. The lipid-rich core provides the bilayer-like structure, while the detergent “rim” stabilizes the lipid hydrophobic tails. However, the energetics that dictate this phase segregation are unknown. We measure the composition-dependent changes in bicelle structure by titrating different detergents into the bicelle and observing the effects of headgroup structure, tail length, and number of tails on bicelle morphology. Using scattering techniques in conjunction with NMR methods, the aggregation structure of each detergent/lipid mixture, as well as the extent of lipid segregation, has been determined. We have used these structural measurements to calculate the chemical potential of mixing lipids and detergents, demonstrating the value of bicelles as a platform with which lipid-lipid interactions may be measured.

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