Short chain nonionic detergents for example can affect the functional properties of a membrane protein (1). It seems clear that removing the native lipid bilayer from the membrane protein can interfere with the function of the protein. One way to mimic the native lipid membrane are MSP-nanodiscs (Fig. 1) or detergent-free polymer systems (Fig. 2) (Styrene-maleic acid co-polymers (SMAs) (2), Diisobutylene-maleic acid (DIBMA)) (3,4). With the latter you can directly extract membrane proteins from cells without an intermediate step of detergent solubilization (5). Synthetic polymers have to carry a styrene or maleic acid group himself to solubilize proteins.
SMAs have big advantages in contrast to many detergents and are successfully used for many applications (6). The drawback of SMAs is a high absorbance of ultraviolet light in solution with an absorbance maximum at 280 nm. The main reason for this peak at 280 nm are aromatic amino acids like tryptophan or phenylalanine, SMA itself carries an aromatic ring. So quantitative protein concentration measuring of your sample is not possible during the process of membrane protein solubilization, stabilization and purification. With PureCube DIBMA from Cube Biotech you can solubilize, stabilize and purify your protein detergent-free and measure your protein concentration without any problems.
Fig.3 : SDS Page showing solubilized membrane-protein fractions of E. coli. 10 mM (0.5 % (w/v)) DDM and 3 mM (2.5 % (w/v)) DIBMA was used. The figure is taken from Grethen et. al. 2017 (7).
Fig.4: Chemical structural formula of diisobutylene-maleic acid (DIBMA).