Hydrophobic variants of tandem malonate-based glucosides (TMG) for membrane protein study

Abstract

Detergents are essential tools for studying membrane proteins. Unlike soluble proteins, membrane protein solubilization is challenging because of their tendency to aggregate and denature when extracted from membranes into an aqueous buffer. However, detergents encapsulate the membrane proteins to preserve their intact structure and facilitate structural analysis. Although conventional detergents have been used to extract membrane proteins, there are limitations in dealing with stabilization of various membrane proteins by one detergent. Here, we introduce the hydrophobic variants of the tandem malonate-based glucosides (TMGs) previously reported. The newly synthesized amphiphiles are classified according to the structural modification of the hydrophobic tandem linker: TMG-Ms (methylene linker), TMG-Ps (propylene linker with an additional alkyl chain). The variation of TMGs presented an ameliorated efficacy compared with a conventional detergent, n-dodecyl-β-D-maltopyranoside (DDM), for tested transporter. In addition, some TMG-Ms and TMG-Ps showed significantly improved abilities to stabilize the membrane proteins in comparison with TMG-As as a counterpart. The effects of the individual TMGs on protein stability differed with the alkyl chain length and the change in hydrophobic group structure of detergents, leading to conclusion on the detergent-detergent interaction when they form self-assemblies. Therefore, this research not only proposes novel detergent tools for membrane protein study but also shows the correlation of the hydrophobicity and efficacy of the detergents in stabilizing membrane proteins.