Tandem malonate-based glucosides (TMGs) for membrane protein structural studies

Hazrat Hussain,Jonas S Mortensen,Brian K Kobilka,Yang Du,Claus J Loland,Pil Seok Chae,Claudia Santillan,Juyeon Go,Parameswaran Hariharan,Orquidea Ribeiro,Bernadette Byrne,Lan Guan

doi:10.1038/s41598-017-03809-3

Abstract

High-resolution membrane protein structures are essential for understanding the molecular basis of diverse biological events and important in drug development. Detergents are usually used to extract these bio-macromolecules from the membranes and maintain them in a soluble and stable state in aqueous solutions for downstream characterization. However, many eukaryotic membrane proteins solubilized in conventional detergents tend to undergo structural degradation, necessitating the development of new amphiphilic agents with enhanced properties. In this study, we designed and synthesized a novel class of glucoside amphiphiles, designated tandem malonate-based glucosides (TMGs). A few TMG agents proved effective at both stabilizing a range of membrane proteins and extracting proteins from the membrane environment. These favourable characteristics, along with synthetic convenience, indicate that these agents have potential in membrane protein research.

Highlights

High-resolution membrane protein structures are essential for understanding the molecular basis of diverse biological events and important in drug development
Since the optimal balance between hydrophilicity and hydrophobicity is known to be essential for effective stabilization of membrane proteins[30], detergent alkyl chain length was varied from C11 to C14
The tandem malonate-based glucosides (TMGs)-Ts were overall better than the TMG-As at stabilizing all the tested membrane proteins except melibiose permease of Salmonella typhimurium (MelBSt)

Summary

Introduction

High-resolution membrane protein structures are essential for understanding the molecular basis of diverse biological events and important in drug development. (LPDs)[26], and β-peptide (BPs)[27] were developed as alternatives to small amphiphilic molecules Some of these membrane-mimetic systems contain a patch of lipid bilayer stabilized by surrounding amphipathic agents, as exemplified by bicelles and nanodiscs (NDs)[28, 29]. We designed and synthesized novel glucosides by connecting two malonate-based core units via an alkyl or thioether linkage, designated alkyl chain- or thioether-linked tandem malonate-based glucosides (TMG-As/Ts) (Fig. 1) When these agents were evaluated for multiple membrane protein systems, TMG representatives conferred enhanced stability to most of the tested proteins compared to DDM, with the best detergent variable depending on the target protein

Methods

Results

Conclusion