Two new surfactants, F 5 OM and F 5 DM, were designed as partially fluorinated analogs of ndodecyl-β-D-maltoside (DDM). The micellization properties and the morphologies of the aggregates formed by the two surfactants in water and phosphate buffer were evaluated by NMR spectroscopy, surface tension measurement (SFT), isothermal titration calorimetry (ITC), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and analytical ultracentrifugation (AUC). As expected, the critical micellar concentration (CMC) was found to decrease with chain length of the fluorinated tail from 2.1-2.5 mM for F 5 OM to 0.3-0.5 mM for F 5 DM, and micellization was mainly entropy-driven at 25°C. Close to their respective CMC, the micelle sizes were similar for both surfactants i.e. 7 and 13 nm for F 5 OM and F 5 DM, respectively and both increased with concentration forming 4 nm diameter rods with maximum dimensions of 50 and 70 nm, respectively, at a surfactant concentration of ~30 mM. The surfactants were found to readily solubilize lipid vesicles and extract membrane proteins (MPs) directly from Escherichia coli membranes. They were found more efficient than the commercial fluorinated detergent F 6 H 2 OM over a broad range of concentrations (1-10 mM) and even better than DDM at low concentrations (1-5 mM). When transferred into the two new surfactants, the thermal stability of the proteins bacteriorhodopsin (bR) and FhuA were higher than in the presence of their solubilization detergents and similar to that in DDM; furthermore, bR was stable over several months. The membrane enzymes SpNOX and BmrA were not as active as in DDM micelles but similarly active as in F 6 OM. Together, these findings indicate both extracting and stabilizing properties of the new maltose-based fluorinated surfactants, making them promising tools in MPs applications.

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We report herein the synthesis of a series of fluorinated surfactants with a glucose moiety as a polar head group and whose alkyl chain was varied in length and in fluorine/hydrogen ratio. They were synthesized in two or four steps in 20 to 50% overall yields allowing gram-scale synthesis. Their solubility in water is between 0.2 and 13.8 g/L, which indicates low water solubility. Two derivatives of the series were found to form micelles in water at ∼11 mM. Their hydrophilic−lipophilic balance was determined both by Griffin's and Davies' methods; they may exhibit a "harsh" character toward membrane proteins. This, combined with their low water solubility, suggest that they could advantageously be used in detergent mixtures containing a "mild" detergent. Finally, the potency of one of the derivatives, F 3 H 5 -β-Glu, to act as an additive for the crystallization of AcrB was evaluated in detergent mixtures with n-dodecyl-β-D-maltopyranoside (DDM). Among the six crystallization conditions investigated, adding F 3 H 5β-Glu improved the crystallization for three of them, as compared to control drops without additives. Moreover, preliminary tests with other compounds of the series showed that none of them hampered crystallization and suggested improvement for three of them. These novel glucose-based fluorinated detergents should be regarded as potential additives that could be included in screening kits used in crystallization.