The non-Newtonian behavior of detergents during concentration is increased by macromolecules, in trans, and results in their over-concentration

• DOI: 10.1016/j.biochi.2022.09.004
• Publication Date: 2022-09-07T15:39:01Z
• Authors: Alexia Gobet; Veronica Zampieri; Sandrine Magnard; Eva Pebay-Peyroula; Pierre Falson; Vincent Chaptal
• Keywords: Detergents concentration; 0301 basic medicine; 570; Polymers; [SDV.BBM]Life Sciences [q-bio]/Biochemistry; Detergents; Membrane Proteins; Membrane protein concentration; Non-Newtonian effect; 03 medical and health sciences; 616; [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology; Molecular Biology

Concentration of pure membrane proteins in detergent solution results in detergent concentration, albeit in unknown amounts. This phenomenon is observed in every lab working on membrane proteins, but has seldom been investigated. In this study, we explored the behavior of detergents mixed with membrane proteins during the step of sample concentration using centrifugal devices. We show that detergent over-concentrate with the presence of polymers, typically membrane or soluble proteins but also polysaccharides. The over-concentration of detergents depends on centrifugal force applied to the device. With the use of a specific dye, we observed the formation of a mesh on the concentrator device. Importantly, reducing the centrifugal speed allows to reduce the concentration of detergents when mixed to macromolecules, as tested with 3 different membrane proteins. All together, these results highlight the non-Newtonian behavior of detergents and provides a solid framework to investigators to improve drastically biochemical and structural studies of membrane proteins.