Use of dynamic light scattering and small-angle X-ray scattering to characterize new surfactants in solution conditions for membrane-protein crystallization

Abstract

The structural and interactive properties of two novel hemifluorinated surfactants, F2H9-β-M and F4H5-β-M, the syntheses of which were based on the structure and hydrophobicity of the well known dodecyl-β-maltoside (DD-β-M), are described. The shape of their micellar assemblies was characterized by small-angle X-ray scattering and their intermicellar interactions in crystallizing conditions were measured by dynamic light scattering. Such information is essential for surfactant phase-diagram determination and membrane-protein crystallization.

Sparingly fluorinated maltoside-based surfactants for membrane-protein stabilization

“…The molar mass and the aggregation number of F 4 H 5 bM micelles were determined from forward intensities to amount to B32 000 g mol À1 and 50 molecules per micelle, respectively; this is less than the corresponding values of F 2 H 9 bM but as expected for this less hydrophobic chain. A thorough determination of micelle dimensions for the three fluorosurfactants was described in Dahani et al 32 The maximum distances in micelle assemblies (D max ) obtained from the pair distribution function P(r) for the three fluorosurfactants ( Fig. 5B) are in agreement with the hydrodynamic diameters obtained from DLS.…”

“…S2, ESI †) and micelle diffusion coefficients (D t ) as functions of surfactant concentration. 32 Although large aggregates (4100 nm) appeared in intensity-weighted size distributions for F 2 H 9 bM (Fig. S2B, ESI †) and F 4 H 5 bM (Fig.…”

“…We considered the partial specific volumes, % v, from ref. 32 reported in Table S1 (ESI †). Values calculated from chemical composition 33 differ somewhat but are in the same range, that is, 0.718, 0.629, and 0.564 mL g À1 for F 2 H 9 bM, F 4 H 5 bM, and F 6 H 2 bM, respectively.…”

Multi-channelin situdynamic light scattering instrumentation enhancing biological small-angle X-ray scattering experiments at the PETRA III beamline P12

“…However, a prerequisite for SAXS experiments usually is a monodisperse and well defined sample solution. In order to determine the dispersity of a solution prior to a SAXS experiment and to verify SAXS data, DLS is a well accepted method (Regini et al, 2010;Carvalho et al, 2014;Dahani et al, 2015;Khan et al, 2017). A combined DLS-SAXS setup allows a direct cross-verification and calculation of the ratio of gyration radius (R g ) and R H , i.e.…”

Hybrid Fluorinated and Hydrogenated Double-Chain Surfactants for Handling Membrane Proteins

“…Figure shows that both surfactants self-organize into well-defined assemblies with apparent hydrodynamic diameters of ∼7 and ∼11 nm, respectively, suggesting the formation of rather small micelles. When compared to the popular detergent, n -dodecyl-β- d -maltoside (DDM) that forms globular micelles of ∼7 nm hydrodynamic diameter, its perfluorinated analogue (F 6 OM) forms rodlike micelles of 30 nm hydrodynamic diameter with 60 nm maximal length. , Upon dilution, no significant difference in the Contin distribution was observed for both compounds (data not shown). The slightly larger micelles observed for compound 2 may arise from the lower polarity of the ether bond, which would make the hydrogenated chain closer to the main chain leading to a bulkier hydrophobic moiety as compared to compound 1 .…”