Tandem Facial Amphiphiles for Membrane Protein Stabilization

Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society (Impact Factor: 12.11). 11/2010; 132(47):16750-2. DOI: 10.1021/ja1072959
Source: PubMed


We describe a new type of synthetic amphiphile that is intended to support biochemical characterization of intrinsic membrane proteins. Members of this new family displayed favorable behavior with four of five membrane proteins tested, and these amphiphiles formed relatively small micelles.

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    • "The most intriguing aspect of the discrepancy between the two binding site models from Javitch and colleagues and the data from the laboratory of Gouaux is that it has not been possible to reproduce the two-leucine stoichiometry pr. LeuT in Gouaux' laboratory even when they attempted to reproduce the preparation of protein according to the methods of Javitch and colleagues or in the recently developed lauryl maltose neopentyl glycol (MNG-3) detergent [91] which has been shown to increase stability and functionality of purified LeuT [10] [11] [12]. Neither has it been possible for them to reduce [ 3 H]leucine binding by 50% by introducing the L400S mutant or by the addition of clomipramine which should bind exclusively to the S2 site [91]. "
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    • "Amphiphilic polymers (amphipols) [17] [18], nanodiscs (NDs) [18] [19] [20] [21], and lipodisqs [22] are innovative approaches to overcome the limitation of current tools for membrane protein stability. Tandem facial amphiphiles (TFAs) [23] and hemifluorinated surfactants (HFSs) [24] [25] [26] are other examples of recent inventions that have shown to be excellent in retaining the native structures of delicate membrane proteins. Amphipathic peptides such as lipopeptide detergents (LPDs) [27] and short designer peptides [28] proved to be effective for several classes of membrane protein systems as well. "
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    ABSTRACT: Membrane proteins operate in unique cellular environments. Once removed from their native context for the purification that is required for most types of structural or functional analyses, they are prone to denature if not properly stabilized by membrane mimetics. Detergent micelles have prominently been used to stabilize membrane proteins in aqueous environments as their amphipathic nature allows for shielding of the hydrophobic surfaces of these bio-macromolecules while supporting solubility and monodispersity in water. This study expands the utility of branched diglucoside-bearing tripod agents, designated ganglio-tripod amphiphiles, with introduction of key variations in their hydrophobic sections and shows how these latter elements can be fine-tuned to maximize membrane protein solubilization while preserving characteristics of these molecules that afford stabilization of rather fragile assemblies. Their efficacy rivals benchmark detergents heavily used today, such as n-dodecyl-β-D-maltoside.
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    • "It is possible that this amphiphile may be more suitable for vapor diffusion crystallization of GPCRs than the MNGs because of its tendency to form small protein– detergent complexes. Further advances in the area of alternative detergents have the potential to facilitate structural studies of GPCRs as well as other integral membrane proteins [77] [78]. "
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