Novel approaches to understand function and explore inhibition within protein-membrane interfaces.

Abstract

Despite their importance in biology and disease, peripheral membrane proteins (PMPs) have presented a significant challenge. This class of proteins reversibly binds to membranes to perform function. High-resolution functional and structural studies of PMPs are often limited to their water-solubilized state due to technical limitations. Large blind spots in functional interactions within membranes are therefore common and require methodological and technological advancement to overcome. Additionally, inhibitor development for PMPs in their functionally relevant, membrane embedded state is difficult, often impossible, using current methods. We address these barriers by utilizing newly developed membrane mimicking reverse micelles (mmRMs), which house PMPs within a spherical, nanoscale assembly of lipids. Studies using mmRMs have been applied to several PMPs, including glutathione peroxidase 4 (GPx4). Use of mmRMs to investigate PMPs has proven advantageous over other membrane models for various NMR-based experimental approaches. Observations of protein-lipid interactions and lipid specificity determinations are greatly enhanced. Applying mmRMs to PMP structural analysis promises to reveal greater detail of the effects of membrane binding. Finally, mmRMs are helping to overcome challenges associated with inhibitor discovery and design for membrane embedded PMPs. mmRM-based screening for fragments in the protein-membrane interface reveals building blocks that may be advanced to inhibitors. Furthermore, discovery of small-molecule binders within membrane interfaces promises to reveal fundamental properties of this largely unexplored chemical space. Together, these approaches promise to advance our knowledge and add to the tool belt for the important and elusive peripheral membrane category of proteins.