Additive Action of Two or More Solutes on Lipid Membranes

Abstract

A wide variety of biological processes, pharmaceutical applications, and technical procedures is based on the combined action of two or more soluble compounds to perturb, permeabilize, or lyse biological membranes. Here we present a general model describing the additive action of solutes on the properties of membranes or micelles. The onset and completion of membrane solubilization induced by two surfactants (lauryl maltoside, with nonyl maltoside, octyl glucoside, or CHAPS, respectively) are very well described by our model on the basis of their individual partition coefficients, cmc's, and critical mole ratios R e sat and R e sol as detected by isothermal titration calorimetry. This suggests that the thermodynamic phase transition is governed by a single parameter (e.g., spontaneous curvature) in spite of the complexity of structural changes. Such surfactant mixtures show unique features such as nonlinear solubilization boundaries and concentration-dependent effective partition coefficients. Other phenomena such as membrane leakage are predicted to obey additive action if the solutes act via the same mechanism (e.g., toroidal pore formation) but deviate from the model in the case of independent, synergistic, or antagonistic action.

Membrane solubilisation and reconstitution by octylglucoside: Comparison of synthetic lipid and natural lipid extract by isothermal titration calorimetry

“…We encountered neither problem, as fitting the SAT and SOL boundaries with independently adjustable c D aq,SAT and c D aq,SOL parameters yielded values virtually identical to those listed in Table 1 (1) and (2), respectively; fitting parameters are given in Table 1. values for the OG/POPC system are in good agreement with previously reported data [23,41]. The ITC titrations employing POPC and E. coli polar lipid extract revealed similar overall patterns on the qualitative level (compare Figs.…”

“…Furthermore, PCs are available commercially in high purities and at low costs. Thus, the application of ITC to lipid bilayers rich in PC lipids is well-established, and thermodynamic parameters of detergent/lipid interactions and bilayer-to-micelle transitions have been described for a broad spectrum of detergents [12,[17][18][19][20][21][22][23].…”

“…During the last two decades, isothermal titration calorimetry (ITC) has been established as an exceptionally powerful technique for monitoring the compositiondependent phase behaviour of detergent/lipid mixtures (see [12,[17][18][19][20][21][22][23] for examples, [24,25] for reviews, and [26] for a step-by-step protocol). More recently, it has also been applied to characterising the lipid interactions of lipopeptides with detergent-like properties [27][28][29][30].…”

A general path for large-scale solubilization of cellular proteins: From membrane receptors to multiprotein complexes

“…Some proteins are particularly hard to solubilize with a single detergent, in such cases we have successfully employed two surfactants mixtures, ionic–non-ionic or non-ionic–non-ionic for their solubilization [26–28]. For example, the ionic–non-ionic combination is particularly useful for extraction of proteins from E. coli pellets.…”

Inhomogeneities in sodium decylsulfate doped 1,2-dipalmitoylphosphatidylcholine bilayer

“…Due to their ability to enter and disrupt the membrane bilayer, surfactants have been used in biochemistry as membrane solubilizers [6][7][8][9][10] with the aim to isolate and purify some of its constituents, in primis proteins.…”