Cyclohexyl-alpha maltoside as a highly efficient tool for membrane protein studies

Membrane proteins (MPs) constitute a large fraction of the proteome, but exhibit physicochemical characteristics that impose challenges for successful sample production crucial for subsequent biophysical studies. In particular, MPs have to be extracted from the membranes in a stable form. Reconstitution into detergent micelles represents the most common procedure in recovering MPs for subsequent analysis. n-dodecyl-beta-D-maltoside (DDM) remains one of the most popular conventional detergents used in production of MPs. Here we characterize the novel DDM analogue 4-trans-(4-trans-propylcyclohexyl)-cyclohexyl alpha-maltoside (t-PCC alpha M), possessing a substantially lower critical micelle concentration (CMC) than the parental compound that represents an attractive feature when handling MPs. Using three different types of MPs of human and prokaryotic origin, i. e., a channel, a primary and a secondary active transporter, expressed in yeast and bacterial host systems, respectively, we investigate the performance of t-PCC alpha M in solubilization and affinity purification together with its capacity to preserve native fold and activity. Strikingly, t-PCC alpha M displays favorable behavior in extracting and stabilizing the three selected targets. Importantly, t-PCC alpha M promoted extraction of properly folded protein, enhanced thermostability and provided negatively-stained electron microscopy samples of promising quality. All-in-all, t-PCC alpha M emerges as competitive surfactant applicable to a broad portfolio of challenging MPs for downstream structure-function analysis.