Membrane Proteins

Deuterated phospholipids and detergents for structural studies of membrane proteins

Membrane proteins make up between 20% and 30% of all expressed proteins. They are of great interest in structural biology and pharmaceutical drug development, representing more than half of all present-day drug targets.

Membrane proteins have hydrophobic exteriors, are relatively dynamic, and are produced at relatively low levels. These factors make it difficult to obtain stable preparations for NMR analysis, but phospholipids and detergents can be used to ensure proper solubilization and stability. Despite their significant functional importance, determining membrane protein structures remains far more challenging than for globular proteins — fortunately, a wide range of sample preparation conditions is available for both solution- and solid-state NMR.

Why Use Deuterated Phospholipids & Detergents

Eurisotop offers deuterated phospholipids and detergents manufactured by FB Reagents, a specialist supplier since 2008 and a partner in the first NMR structure determination of an integral membrane protein. Using deuterated, rather than protonated, lipids and detergents to prepare membrane protein samples provides several key advantages:

Spectral simplification — removes unwanted ¹H signals from the membrane mimic, so the spectrum reflects the protein of interest rather than the surrounding lipid or detergent.
Easier signal detection — simplifies interpretation of multidimensional NMR experiments by reducing background signal overlap.
Reduced dipolar relaxation effects — can lead to signal enhancement in certain systems, improving spectral resolution.
Preserved fold & activity — helps the protein assume its correct three-dimensional fold and remain functionally active during the experiment.

Choosing a Membrane Mimetic

Membrane proteins require the correct chemical environment to assume their proper fold and mimic the three-dimensional structures found in vivo. Depending on the protein and the NMR technique used, several sample environments are available:

Detergent Micelles

The most common environment for solution-state NMR, using detergents such as DDM, β-OG, or LDAO to form small, fast-tumbling particles suited to high-resolution spectra.

Bicelles

Disc-shaped lipid/detergent assemblies offering a more native-like bilayer environment than pure detergent micelles.

Lipid Nanodiscs

Detergent-free, constrained lipid bilayers that preserve a near-native membrane environment for structural refinement.

Solid-State Preparations

Reconstituted lipid bilayers used for solid-state NMR, avoiding the size and tumbling constraints of solution-state methods.

Key Deuterated Detergents & Lipids

DDM (n-Dodecyl-β-D-maltoside) — a widely used non-ionic detergent, available deuterated (d₂₅) for routine membrane protein solubilization.
β-OG (n-Octyl-β-D-glucoside) — a shorter-chain non-ionic detergent, available in aliphatic-chain-deuterated (d₁₇) and perdeuterated (d₂₄) forms.
LDAO — a detergent whose deuterated form contributed to determining the first 3D NMR structure of an integral membrane protein, VDAC-1.
Deuterated phospholipids — used to build bicelles and nanodiscs that closely mimic native membrane environments.

50%+ of present-day drug targets are membrane proteins