Self-Organization of Alpha Helical Proteins in Bioinspired Membranes and Vesicles

ABSTRACT

A fundamental understanding of protein-protein and protein-lipid interactions under various conditions can reveal the energy pathways in photosynthetic bacterial membranes. In this study, we examine the role of key factors such as bilayer curvature, the concentration, helical separation and hydrophobic mismatch of proteins on their self-organization in bilayers. We also develop an understanding of the physical factors underlying the aggregation of proteins. We determine the impact of bilayer curvature by comparing the aggregation of proteins in membranes and vesicles. We identify a threshold helical separation below which small, stable aggregates are observed. Large, unstable protein aggregates are observed above the threshold separation. We examine the effect of the deformations incurred by the proteins via their concentration, and show the aggregation of the proteins to arise from their deformation-induced displacement. We demonstrate the negative hydrophobic mismatch condition to favor a higher degree of protein aggregation. We adopt the Molecular Dynamics simulation technique along with a coarse-grained force field to capture the behavior spanning extensive spatiotemporal scales. Our results can guide experimental studies of bioinspired materials with structure-function properties mimicking those of photosynthetic bacterial membranes, or assist in understanding the organization of inclusions in polymeric matrices.