Reverse Micelle Encapsulation of Membrane-Anchored Proteins for Solution NMR Studies

SummaryPerhaps 5%–10% of proteins bind to membranes via a covalently attached lipid. Posttranslational attachment of fatty acids such as myristate occurs on a variety of viral and cellular proteins. High-resolution information about the nature of lipidated proteins is remarkably sparse, often because of solubility problems caused by the exposed fatty acids. Reverse micelle encapsulation is used here to study two myristoylated proteins in their lipid-extruded states: myristoylated recoverin, which is a switch in the Ca2+ signaling pathway in vision, and the myristoylated HIV-1 matrix protein, which is postulated to be targeted to the plasma membrane through its binding to phosphatidylinositol-4,5-bisphosphate. Both proteins have been successfully encapsulated in the lipid-extruded state and high-resolution NMR spectra obtained. Both proteins bind their activating ligands in the reverse micelle. This approach seems broadly applicable to membrane proteins with exposed fatty acid chains that have eluded structural characterization by conventional approaches.

Graphical AbstractFigure optionsDownload high-quality image (463 K)Download as PowerPoint slideHighlights
► Reverse micelle encapsulation technology has been applied to myristoylated proteins
► Excellent solution NMR spectra of encapsulated myristoylated proteins are obtained
► Encapsulated myristoylated recoverin and HIV-1 matrix protein are in the lipid-extruded state
► The HIV-1 matrix protein binding site for PI(4,5)P2 can be directly determined