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Stackhouse CI, Pierson KN, Labrecque CL, Mawson C, Berg J, Fuglestad B, Nucci NV. Characterization of 10MAG/LDAO reverse micelles: Understanding versatility for protein encapsulation. Biophys Chem 2024; 311:107269. [PMID: 38815545 PMCID: PMC11225088 DOI: 10.1016/j.bpc.2024.107269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/01/2024]
Abstract
Reverse micelles (RMs) are spontaneously organizing nanobubbles composed of an organic solvent, surfactants, and an aqueous phase that can encapsulate biological macromolecules for various biophysical studies. Unlike other RM systems, the 1-decanoyl-rac-glycerol (10MAG) and lauryldimethylamine-N-oxide (LDAO) surfactant system has proven to house proteins with higher stability than other RM mixtures with little sensitivity to the water loading (W0, defined by the ratio of water to surfactant). We investigated this unique property by encapsulating three model proteins - cytochrome c, myoglobin, and flavodoxin - in 10MAG/LDAO RMs and applying a variety of experimental methods to characterize this system's behavior. We found that this surfactant system differs greatly from the traditional, spherical, monodisperse RM population model. 10MAG/LDAO RMs were discovered to be oblate ellipsoids at all conditions, and as W0 was increased, surfactants redistributed to form a greater number of increasingly spherical ellipsoidal particles with pools of more bulk-like water. Proteins distinctively influence the thermodynamics of the mixture, encapsulating at their optimal RM size and driving protein-free RM sizes to scale accordingly. These findings inform the future development of similarly malleable encapsulation systems and build a foundation for application of 10MAG/LDAO RMs to analyze biological and chemical processes under nanoscale confinement.
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Affiliation(s)
- Crystal I Stackhouse
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Kali N Pierson
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Courtney L Labrecque
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
| | - Cara Mawson
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Joshua Berg
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States
| | - Brian Fuglestad
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States; Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States.
| | - Nathaniel V Nucci
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
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2
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Walters SH, Castillo AJ, Develin AM, Labrecque CL, Qu Y, Fuglestad B. Investigating protein-membrane interactions using native reverse micelles constructed from naturally sourced lipids. Protein Sci 2023; 32:e4786. [PMID: 37746759 PMCID: PMC10578115 DOI: 10.1002/pro.4786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/15/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
Advancing the study of membrane associated proteins and their interactions is dependent on accurate membrane models. While a variety of membrane models for high-resolution membrane protein study exist, most do not reflect the diversity of lipids found within biological membranes. In this work, we have developed native reverse micelles (nRMs) formulated with lipids from multiple eukaryotic sources, which encapsulate proteins and enable them to interact as they would with a biological membrane. Diverse formulations of nRMs using soy lecithin, porcine brain lipids, or bovine heart lipids combined with n-dodecylphosphocholine were developed and characterized by dynamic light scattering and 31 P-NMR. To optimize protein encapsulation, ubiquitin was used as a standard and protein NMR verified minimal changes to its structure. Peripheral membrane proteins, which bind reversibly to membranes, were encapsulated and include glutathione peroxidase 4 (GPx4), phosphatidylethanolamine-binding protein 1 (PEBP1), and fatty acid binding protein 4 (FABP4). All three proteins showed anticipated interactions with the membrane-like inner surface of the nRMs as assessed by protein NMR. The nRM formulations developed here allow for efficient, high-resolution study of membrane interacting proteins up to and beyond ~21 kDa, in a more biologically relevant context compared to other non-native membrane models. The approach outlined here may be applied to a wide range of lipid extracts, allowing study of a variety of membrane associated proteins in their specific biological context.
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Affiliation(s)
- Sara H. Walters
- Department of ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Abdul J. Castillo
- Department of ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Angela M. Develin
- Department of ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | | | - Yun Qu
- Department of ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Brian Fuglestad
- Department of ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
- Institute for Structural Biology, Drug Discovery and DevelopmentVirginia Commonwealth UniversityRichmondVirginiaUSA
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3
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Miller SL, Gaidamauskas E, Altaf AA, Crans DC, Levinger NE. Where Are Sodium Ions in AOT Reverse Micelles? Fluoride Anion Probes Nanoconfined Ions by 19F Nuclear Magnetic Resonance Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023. [PMID: 37219990 DOI: 10.1021/acs.langmuir.3c00649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Confining water to nanosized spaces creates a unique environment that can change water's structural and dynamic properties. When ions are present in these nanoscopic spaces, the limited number of water molecules and short screening length can dramatically affect how ions are distributed compared to the homogeneous distribution assumed in bulk aqueous solution. Here, we demonstrate that the chemical shift observed in 19F NMR spectroscopy of fluoride anion, F-, probes the location of sodium ions, Na+, confined in reverse micelles prepared from AOT (sodium dioctyl sulfosuccinate) surfactants. Our measurements show that the nanoconfined environment of reverse micelles can lead to extremely high apparent ion concentrations and ionic strength, beyond the limit in bulk aqueous solutions. Most notably, the 19F NMR chemical shift trends we observe for F- in the reverse micelles indicate that the AOT sodium counterions remain at or near the interior interface between surfactant and water, thus providing the first experimental support for this hypothesis.
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Affiliation(s)
- Samantha L Miller
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Ernestas Gaidamauskas
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Ataf Ali Altaf
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
- Department of Chemistry, University of Okara, Okara 56300, Pakistan
| | - Debbie C Crans
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Nancy E Levinger
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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4
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Labrecque CL, Nolan AL, Develin AM, Castillo AJ, Offenbacher AR, Fuglestad B. Membrane-Mimicking Reverse Micelles for High-Resolution Interfacial Study of Proteins and Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3676-3686. [PMID: 35298177 DOI: 10.1021/acs.langmuir.1c03085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Despite substantial advances, the study of proteins interacting with membranes remains a significant challenge. While integral membrane proteins have been a major focus of recent efforts, peripheral membrane proteins (PMPs) and their interactions with membranes and lipids have far less high-resolution information available. Their small size and the dynamic nature of their interactions have stalled detailed interfacial study using structural methods like cryo-EM and X-ray crystallography. A major roadblock for the structural analysis of PMP interactions is limitations in membrane models to study the membrane recruited state. Commonly used membrane mimics such as liposomes, bicelles, nanodiscs, and micelles are either very large or composed of non-biological detergents, limiting their utility for the NMR study of PMPs. While there have been previous successes with integral and peripheral membrane proteins, currently employed reverse micelle (RM) compositions are optimized for their inertness with proteins rather than their ability to mimic membranes. Applying more native, membrane-like lipids and surfactants promises to be a valuable advancement for the study of interfacial interactions between proteins and membranes. Here, we describe the development of phosphocholine-based RM systems that mimic biological membranes and are compatible with high-resolution protein NMR. We demonstrate new formulations that are able to encapsulate the model soluble protein, ubiquitin, with minimal perturbations of the protein structure. Furthermore, one formula, DLPC:DPC, allowed the encapsulation of the PMPs glutathione peroxidase 4 (GPx4) and phosphatidylethanolamine-binding protein 1 (PEBP1) and enabled the embedment of these proteins, matching the expected interactions with biological membranes. Dynamic light scattering and small-angle X-ray scattering characterization of the RMs reveals small, approximately spherical, and non-aggregated particles, a prerequisite for protein NMR and other avenues of study. The formulations presented here represent a new tool for the study of elusive PMP interactions and other membrane interfacial investigations.
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Affiliation(s)
- Courtney L Labrecque
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Aubree L Nolan
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Angela M Develin
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Abdul J Castillo
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Adam R Offenbacher
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, United States
| | - Brian Fuglestad
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States
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5
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Harada M, Sakai H, Fukunaga Y, Okada T. Hydration of bromide at reverse micelle interfaces studied by X-ray absorption fine structure. J Colloid Interface Sci 2021; 599:79-87. [PMID: 33933799 DOI: 10.1016/j.jcis.2021.04.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 10/21/2022]
Abstract
Nanoconfined water exhibits various interesting properties, which are not only of fundamental importance but also of practical use. Because reverse micelles (RMs) provide versatile ways to prepare nanoconfined water, the understanding of their physicochemical properties is essential for developing efficient applications. Although the water properties in the RMs could be affected by its interaction with the RM interface, the details have not been well understood. This study focuses on the local structures of Br- in hexadecyltrimethylammonium bromide (HTAB) RMs formed in chloroform and 10% hexanol/heptane. The dependence in Br- hydration on the molar ratio of water to HTAB (w) is investigated using X-ray absorption fine structure (XAFS). These systems cover a wide range of w values (0-30) and allow us to study the impact of this parameter on the local structure of Br- at the RM interface, which comprises water, surfactant headgroups, and organic solvent components. The presence of multiple scattering paths complicates the XAFS spectra and makes it difficult to analyze them using standard fitting methods. The linear combination of the spectra corresponding to the individual scattering paths captures the molecular processes that occur at the RM interface upon increasing w. The maximum hydration number of Br- is found to be 4.5 at w > 15, suggesting that although most of the ions remain at the interface as partly hydrated ions, some of them dissociate as completely hydrated ones.
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Affiliation(s)
- Makoto Harada
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan.
| | - Hinako Sakai
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | - Yu Fukunaga
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan
| | - Tetsuo Okada
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan.
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6
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Ren D, Xu J, Chen N, Ye Z, Li X, Chen Q, Ma S. Controlled synthesis of mesoporous silica nanoparticles with tunable architectures via oil-water microemulsion assembly process. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.125773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Sofronov O, Bakker HJ. Slow Proton Transfer in Nanoconfined Water. ACS CENTRAL SCIENCE 2020; 6:1150-1158. [PMID: 32724849 PMCID: PMC7379388 DOI: 10.1021/acscentsci.0c00340] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Indexed: 06/11/2023]
Abstract
The transport of protons in nanoconfined environments, such as in nanochannels of biological or artificial proton conductive membranes, is essential to chemistry, biology, and nanotechnology. In water, proton diffusion occurs by hopping of protons between water molecules. This process involves the rearrangement of many hydrogen bonds and as such can be strongly affected by nanoconfinement. We study the vibrational and structural dynamics of hydrated protons in water nanodroplets stabilized by a cationic surfactant using polarization-resolved femtosecond infrared transient absorption spectroscopy. We determine the time scale of proton hopping in the center of the water nanodroplets from the dynamics of the anisotropy of the transient absorption signals. We find that in small nanodroplets with a diameter <4 nm, proton hopping is more than 10 times slower than in bulk water. Even in relatively large nanodroplets with a diameter of ∼7 nm, we find that the rate of proton hopping is slowed by ∼4 times compared with bulk water.
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8
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Zhang Y, Zhen B, Hu Y, Liang G, Feng Y. A reverse micellar system with Triton X-100: effect of surfactant polydispersity and preparation of monodisperse silica nanoparticles. SOFT MATTER 2020; 16:383-389. [PMID: 31830193 DOI: 10.1039/c9sm02182e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Reverse micellar systems possess a characteristic nanoscale water-in-oil (w/o) structure and can offer mild conditions as a unique and versatile reaction medium. Reverse microemulsions containing water/TX-100 + hexanol/hexane are studied in this work through experimental techniques and simulation methods. Surfactant dosages and water amount affect the micellar structure profoundly, and the polydispersity of the surfactant molecules affects the micellar structure remarkably. TX-100 with 9-10 EO units can form micelles in a simply piling way, while TX-100 with 5-10 EO units endows the micelles with a hierarchical micellar interface and a more compact structure, leading to monodisperse micelles with a smaller diameter. Water in the polar cores has three states. In the reverse micellar system using TX-100 with 9-10 EO units, hydrolysis of tetraethoxysilane happens rapidly and the formed silica gels are apt to aggregate, resulting in polydisperse silica nanoparticles. For the micellar system using TX-100 with 5-10 EO units, the micellar hierarchical distributed interface facilitates the material exchange of tetraethoxysilane and limits the hydrolysis of tetraethoxysilane inside the micelles, providing monodisperse silica nanoparticles.
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Affiliation(s)
- Yaping Zhang
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
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9
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Fuglestad B, Kerstetter NE, Bédard S, Wand AJ. Extending the Detection Limit in Fragment Screening of Proteins Using Reverse Micelle Encapsulation. ACS Chem Biol 2019; 14:2224-2232. [PMID: 31550881 DOI: 10.1021/acschembio.9b00537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Detection of very weak (Kd > 10 mM) interactions of proteins with small molecules has been elusive. This is particularly important for fragment-based drug discovery, where it is suspected that the majority of potentially useful fragments will be invisible to current screening methodologies. We describe an NMR approach that permits detection of protein-fragment interactions in the very low affinity range and extends the current detection limit of ∼10 mM up to ∼200 mM and beyond. Reverse micelle encapsulation is leveraged to effectively reach very high fragment and protein concentrations, a principle that is validated by binding model fragments to E. coli dihydrofolate reductase. The method is illustrated by target-detected screening of a small polar fragment library against interleukin-1β, which lacks a known ligand-binding pocket. Evaluation of binding by titration and structural context allows for validation of observed hits using rigorous structural and statistical criteria. The 21 curated hit molecules represent a remarkable hit rate of nearly 10% of the library. Analysis shows that fragment binding involves residues comprising two-thirds of the protein's surface. Current fragment screening methods rely on detection of relatively tight binding to ligand binding pockets. The method presented here illustrates a potential to faithfully discover starting points for development of small molecules that bind to a desired region of the protein, even if the targeted region is defined by a relatively flat surface.
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Affiliation(s)
- Brian Fuglestad
- Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - Nicole E. Kerstetter
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Sabrina Bédard
- Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - A. Joshua Wand
- Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
- Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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10
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Ciszewski RK, Gordon BP, Muller BN, Richmond GL. Takes Two to Tango: Choreography of the Coadsorption of CTAB and Hexanol at the Oil-Water Interface. J Phys Chem B 2019; 123:8519-8531. [PMID: 31513405 DOI: 10.1021/acs.jpcb.9b05775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mixed surfactant systems at the oil-water interface play a vital role in applications ranging widely from drug delivery to oil-spill remediation. Synergistic mixtures are superior emulsifiers and more effective at modifying surface tension than either component alone. Mixtures of surfactants with dissimilar polar head groups are of particular interest because of the additional degree of control they offer. The interplay of hydrophobic and electrostatic effects in these systems is not well understood, in part because of the difficulty in examining their behavior at the buried oil-water interface where they reside. Here, surface-specific vibrational sum frequency spectroscopy is utilized in combination with surface tensiometry and computational methods to probe the cooperative molecular interactions between a cationic surfactant cetyltrimethylammonium bromide (CTAB) and a nonionic alcohol (1-hexanol) that induce the two initially reluctant surfactants to coadsorb synergistically at the interface. A careful deuteration study of CTAB reveals that hexanol cooperates with CTAB such that both molecules preferentially orient at the interface for sufficiently large enough concentrations of hexanol. This work's methodology is unique and serves as a guide for future explorations of macroscopic properties in these complex systems. Results from this work also provide valuable insights into how interfacial ordering impacts surface tensiometry measurements for nonionic surfactants.
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Affiliation(s)
- Regina K Ciszewski
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Brittany P Gordon
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Benjamin N Muller
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Geraldine L Richmond
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
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11
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Fuglestad B, Kerstetter NE, Wand AJ. Site-Resolved and Quantitative Characterization of Very Weak Protein-Ligand Interactions. ACS Chem Biol 2019; 14:1398-1402. [PMID: 31246002 DOI: 10.1021/acschembio.9b00353] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Very weak interactions between small organic molecules and proteins have long been predicted and are expected to have dissociation constants of hundreds of millimolar and above. Unfortunately, quantitative evaluation of binding in a high-resolution structural context for this affinity regime is particularly difficult and often impossible using existing experimental approaches. Here, we show that nanoscale encapsulation of single protein molecules within the water core of reverse micelles enables the detection and evaluation of weak binding interactions at atomic resolution using solution NMR spectroscopy. This strategy is used to survey the interactions of a set of small molecules with the cytokine interleukin-1β (IL-1β). The interaction of IL-1β with these molecules is found to vary from more diffuse and weak binding modes to more specific and with a relatively higher affinity. The interactions detected here cover a large portion of the protein surface and have dissociation constants mostly in the low molar range. These results illustrate the ability of a protein to interact productively with a variety of small molecule functional groups and point to a broader potential to target even relatively featureless protein surfaces for applications in chemical biology and drug discovery.
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Affiliation(s)
- Brian Fuglestad
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Nicole E. Kerstetter
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - A. Joshua Wand
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States
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12
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Chen C, Tian H, Xing S, Li C, Zeng X, He L. Influence of different parameters on reverse micelle extraction combined with acetone precipitation to purify sn-1,3 extracellular lipase from Aspergillus niger GZUF36. Journal of Food Science and Technology 2019; 56:2899-2908. [PMID: 31205345 DOI: 10.1007/s13197-019-03743-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 02/15/2019] [Accepted: 03/20/2019] [Indexed: 11/26/2022]
Abstract
There are few reports on the feasibility of combined reverse micelle extraction and acetone precipitation to obtain electrophoretic pure enzymes. We aimed to purify a sn-1,3 extracellular lipase from a novel Aspergillus niger GZUF36 through this combination in this work. This lipase preliminarily purified by controlling the volume ratio (1:2.5) of crude enzyme solution and acetone. Then, we studied effects of different parameters on reverse micelle extraction. The suitable surfactant, pH, salt and cosolvent and extraction time for forward extraction were 125 mM cetyl trimethylammonium bromide (CTAB), 9.0, 0.075 M NaCl, 10% n-hexanol and 30 min, respectively. Under these conditions, the forward extraction rate reached 90.3% ± 3.2%. The suitable salt, pH, extraction time and short chain alcohol for backward extraction were consecutively 1.5 M KCl, 6.5, 60 min and 10% ethanol. Adding 10% ethanol shows a significant advantage of improvement the extraction rate. Under these optimal conditions, the total extraction rate and purification factor of lipase reached 76.8% and 10.14, respectively. SDS-PAGE showed that molecular weight of the pure protein was 42.7 kDa and TLC exhibited sn-1,3 selectivity of this lipase. LC-MS/MS analysis revealed that the lipase had 297 amino acid residues and was likely to glycosylate. Through the study of different parameters, it demonstrated that the new and simple combination of reverse micelle extraction using CTAB as surfactant and n-hexanol as cosolvent for forward extraction and adding ethanol for backward extraction and acetone precipitation is a promising method to get almost an electrophoretically pure sn-1,3 lipase.
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Affiliation(s)
- Cuicui Chen
- Key Laboratory of Agricultural and Animal Products Store & Processing of Guizhou Province, Guiyang, 550025 China
- 2College of Liquor and Food Engneering, Guizhou University, Guiyang, 550025 China
| | - Hua Tian
- 3College of Life Science, Xinyang Normal University, Xinyang, 464000 Henan China
| | - Shuqi Xing
- Key Laboratory of Agricultural and Animal Products Store & Processing of Guizhou Province, Guiyang, 550025 China
- 2College of Liquor and Food Engneering, Guizhou University, Guiyang, 550025 China
| | - Cuiqin Li
- 4School of Chemistry and Chemical Engineering, Guizhou University, Guiyang, 550025 China
| | - Xuefeng Zeng
- Key Laboratory of Agricultural and Animal Products Store & Processing of Guizhou Province, Guiyang, 550025 China
- 2College of Liquor and Food Engneering, Guizhou University, Guiyang, 550025 China
| | - Laping He
- Key Laboratory of Agricultural and Animal Products Store & Processing of Guizhou Province, Guiyang, 550025 China
- 2College of Liquor and Food Engneering, Guizhou University, Guiyang, 550025 China
- Guizhou Pork Products Research Center of Engineering Technology, Guiyang, 550018 China
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