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Review
. 2024 Jul 3;72(26):14521-14529.
doi: 10.1021/acs.jafc.4c01827. Epub 2024 Jun 21.

Nanodisc Technology: Direction toward Physicochemical Characterization of Chemosensory Membrane Proteins in Food Flavor Research

Sanjai Karanth  1 , Julia Benthin  1   2 , Marina Wiesenfarth  1   2 , Veronika Somoza  1   3   4 , Melanie Koehler  1   5
Affiliations
Review

Nanodisc Technology: Direction toward Physicochemical Characterization of Chemosensory Membrane Proteins in Food Flavor Research

Sanjai Karanth et al. J Agric Food Chem. .

Abstract

Chemosensory membrane proteins such as G-protein-coupled receptors (GPCRs) drive flavor perception of food formulations. To achieve this, a detailed understanding of the structure and function of these membrane proteins is needed, which is often limited by the extraction and purification methods involved. The proposed nanodisc methodology helps overcome some of these existing challenges such as protein stability and solubilization along with their reconstitution from a native cell-membrane environment. Being well-established in structural biology procedures, nanodiscs offer this elegant solution by using, e.g., a membrane scaffold protein (MSP) or styrene-maleic acid (SMA) polymer, which interacts directly with the cell membrane during protein reconstitution. Such derived proteins retain their biophysical properties without compromising the membrane architecture. Here, we seek to show that these lipidic systems can be explored for insights with a focus on chemosensory membrane protein morphology and structure, conformational dynamics of protein-ligand interactions, and binding kinetics to answer pending questions in flavor research. Additionally, the compatibility of nanodiscs across varied (labeled or label-free) techniques offers significant leverage, which has been highlighted here.

Keywords: atomic force microscopy; chemosensory perception; flavor research; kinetics; membrane proteins; nanodiscs; protein structure; protein−ligand interaction.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Overview of commonly used protein reconstitution methods. In the first step, the cell membrane (e.g., HEK 293 cell as shown here) is solubilized by using an effective detergent (a). These detergent monomers surround the protein, maintaining its functionality. These can be purified and then used for measurements, but to increase the stability of the extracted MPs, amphipols were later introduced, which replaced the detergents (c). The detergents can be removed using different procedures; the biobead method (hydrophobic polystyrene adsorbents) is shown here. However, surrounding lipids are absent with the membrane protein in both of these methods. Depending on the downstream application, the detergent-solubilized MPs can be reconstituted into liposomes, forming proteoliposomes (b). These are the most widely used systems so far, despite their demerits. If the same detergent-solubilized MPs are allowed to equilibrate the membrane scaffold protein (MSP), then these form nanodiscs (d) that mimic the cell membrane environment. To eliminate the presence of exogenous lipids and detergents, direct protein extraction from the cell bilayer can be obtained using the SMA polymer, which forms SMA lipid particles (SMALPs) (e). Created with BioRender.com.
Figure 2
Figure 2
Overview of the different biophysical techniques and the corresponding membrane protein properties, which can be explored using MSP nanodiscs or SMALPs. Abbreviations of the methods shown in the figure are as follows: atomic force microscopy (AFM), circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), differential scanning calorimetry (DSC), electron microscopy (EM), electron paramagnetic resonance (EPR) spectroscopy, isothermal calorimetry (ITC), mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), surface plasmon resonance (SPR), small angle X-ray scattering (SAXS), and small angle neutron scattering (SANS). Created with BioRender.com.
Figure 3
Figure 3
Experimental overview representing different physicochemical properties explored using AFM in nanodiscs. The spatiotemporal and morphology of a protein can be obtained by performing high-resolution imaging. The SecYAEG nanodiscs (A) with fluctuations in the cytoplasmic domain are shown here. In the presence of stimulants, the protein’s activity (i.e., open vs closed state) can also be deduced during imaging experiments. Functionalization of the AFM tip with a biomolecule of interest (i.e., agonist, antagonist, peptide, enzyme, etc.) converts the AFM tip to a nanoprobe (B). Using force spectroscopy, one can determine the binding affinity (as binding force), kinetics, and thermodynamics of a protein. Shown here are the changes in binding force histogram (B) on integrin aIIbβ3 (a mechanosensor) nanodiscs with RGD ligand in the presence of nitric oxide radical. Protein unfolding experiments can also be conducted in a similar manner, which provides information about the energetics. Chemical modification of either MSP protein or SMA polymer or protein of interest can convert a nanodisc into a biosensor with its easy immobilization (C). This offers high flexibility in the development of nanotechnological applications. Shown is the attachment of MgtE nanodiscs onto a streptavidin surface (C, left) and immobilization of Drosophila melanogaster odorant receptor 22a nanodiscs on carbon nanotube (C, right). For representation purposes, only MSP nanodiscs are drawn. However, the same can be done with SMALPs as well. (A,C, left) Reproduced from with permission from ref (44). Copyright 2019 Elsevier. Created with BioRender.com
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References

    1. Gohon Y.; Popot J.-L. Membrane protein-surfactant complexes. Current opinion in colloid & interface science 2003, 8 (1), 15–22. 10.1016/S1359-0294(03)00013-X. - DOI
    1. Privé G. G. Detergents for the stabilization and crystallization of membrane proteins. Methods 2007, 41 (4), 388–397. 10.1016/j.ymeth.2007.01.007. - DOI - PubMed
    1. Lee H. J.; Lee H. S.; Youn T.; Byrne B.; Chae P. S. Impact of novel detergents on membrane protein studies. Chem 2022, 8, 980.10.1016/j.chempr.2022.02.007. - DOI
    1. Dürr U. H.; Gildenberg M.; Ramamoorthy A. The magic of bicelles lights up membrane protein structure. Chemical reviews 2012, 112 (11), 6054–6074. 10.1021/cr300061w. - DOI - PMC - PubMed
    1. Lucyanna B.-B.; Gelen R.; Merce C.; Laia R.; Carmen L.-I.; Alfons d. l. M.; Olga L. Structural versatility of bicellar systems and their possibilities as colloidal carriers. Pharmaceutics 2011, 3 (3), 636–664. 10.3390/pharmaceutics3030636. - DOI - PMC - PubMed

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