Calixarene Surfactants

• No refolding
• No mutagenesis/truncation/fusion
• Striking stability improvement
• High purity
• Maintain functional and structural integrities

These reagents can be used to isolate/purify integral membrane proteins with the highest purity levels while keeping their structural and functional integrity (no refolding or mutagenesis). This has a significantly beneficial impact on the quality of the protein and on the success of the proteomics and drug discovery applications.

  Traditional detergents do not stabilize membrane domains as efficiently as natural lipids in membranes, which often leads to a partial to complete loss of activity/stability during protein extraction and purification and preventing crystallization in an active conformation. 

 

1. Calixarene surfactants
   • These molecules are designed to structure the membrane domains of proteins through hydrophobic interactions and a network of salt bridges with the basic residues found at the cytosol-membrane interface of membrane proteins.
2. Fluorinated poly(tris) and bis-glucose surfactants
   • Fluorinated surfactants are unable to extract proteins from membrane, but are useful for membrane protein stabilization in subsequent purification steps as they do not strip natural lipids and other co-factors from the proteins. In addition, the bulky fluorinated tails can not penetrate into the interior and disrupt structure. Fluorinated surfactants often decrease non-specific aggregation and are thought to result in improved distribution on cryo-EM grids and better vitrification for cryo-EM data collection. They are also reported to increase crystallizability.
   • The bis-glucose compounds have a tetradhedral chiral carbon with two polar headgroups (the glucose moieties) and a long hydrophobic fluorinated tail. In this way they resemble the neo-pentyl glycol detergents, such as LMNG that have seen some recent success in structural biology.