Species within the cell membrane (proteins, lipids, etc.) are key components of cellular processes such as homeostasis and disease pathogenesis. Binding interactions to membrane-associated species are extremely difficult to quantify, however, due to the nature and complexity of the cellular membrane. Typically, such interactions are characterized with isolated membrane proteins presented in detergent micelles or other artificial constructs, completely removed from their native environment and often with non-natural covalent modifications. We will describe a label-free method to observe and quantify membrane protein-ligand interactions in reconstituted native membrane environments. This strategy is based on backscattering interferometry (BSI), in which minute changes in the refractive index of the bulk solution caused by cognate ligand-receptor interactions are related to equilibrium binding affinities without the need for extrinsic molecular labeling. This technique has been applied to membrane proteins supported in isotropically-scattering vesicles derived from native cells, allowing observation of a variety of cognate ligand-receptor interactions over a large range of equilibrium binding affinities.

Using backscattering interferometry to observe label-free observations of molecular interactions of membrane-associated species

249th National Meeting (2015)

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