1
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Zambrano P, Manrique-Moreno M, Petit K, Colina JR, Jemiola-Rzeminska M, Suwalsky M, Strzalka K. Differential scanning calorimetry in drug-membrane interactions. Biochem Biophys Res Commun 2024; 709:149806. [PMID: 38579619 DOI: 10.1016/j.bbrc.2024.149806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 03/04/2024] [Accepted: 03/18/2024] [Indexed: 04/07/2024]
Abstract
Differential Scanning Calorimetry (DSC) is a central technique in investigating drug - membrane interactions, a critical component of pharmaceutical research. DSC measures the heat difference between a sample of interest and a reference as a function of temperature or time, contributing essential knowledge on the thermally induced phase changes in lipid membranes and how these changes are affected by incorporating pharmacological substances. The manuscript discusses the use of phospholipid bilayers, which can form structures like unilamellar and multilamellar vesicles, providing a simplified yet representative membrane model to investigate the complex dynamics of how drugs interact with and penetrate cellular barriers. The manuscript consolidates data from various studies, providing a comprehensive understanding of the mechanisms underlying drug - membrane interactions, the determinants that influence these interactions, and the crucial role of DSC in elucidating these components. It further explores the interactions of specific classes of drugs with phospholipid membranes, including non-steroidal anti-inflammatory drugs, anticancer agents, natural products with antioxidant properties, and Alzheimer's disease therapeutics. The manuscript underscores the critical importance of DSC in this field and the need for continued research to improve our understanding of these interactions, acting as a valuable resource for researchers.
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Affiliation(s)
- Pablo Zambrano
- Department of Bioscience, School of Natural Sciences, Technical University of Munich, Lichtenbergstrasse 4, 85748, Garching, Germany.
| | - Marcela Manrique-Moreno
- Faculty of Natural of Exact Sciences, Chemistry Institute, University of Antioquia, A.A. 1226, Medellin, 050010, Antioquia, Colombia
| | - Karla Petit
- LabMAT, Department of Civil and Environmental Engineering, University of Bío-Bío, Concepción, Chile
| | - José R Colina
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Lientur 1457, Concepción 4080871, Chile
| | - Malgorzata Jemiola-Rzeminska
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Mario Suwalsky
- Facultad de Medicina, Universidad Católica de La Santísima Concepción, Concepción, Chile
| | - Kazimierz Strzalka
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland; Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland.
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2
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Biophysical characterisation of SMALPs. Biochem Soc Trans 2021; 49:2037-2050. [PMID: 34643233 DOI: 10.1042/bst20201088] [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: 08/02/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022]
Abstract
Membrane proteins such as receptors, ion channels and transport proteins are important drug targets. The structure-based study of membrane proteins is challenging, especially when the target protein contains both soluble and insoluble domains. Most membrane proteins are insoluble in aqueous solvent and embedded in the plasma membrane lipid bilayer, which significantly complicates biophysical studies. Poly(styrene-co-maleic acid) (SMA) and other polymer derivatives are increasingly common solubilisation agents, used to isolate membrane proteins stabilised in their native lipid environment in the total absence of detergent. Since the initial report of SMA-mediated solubilisation, and the formation of SMA lipid particles (SMALPs), this technique can directly isolate therapeutic targets from biological membranes, including G-protein coupled receptors (GPCRs). SMA now allows biophysical and structural analyses of membrane proteins in solution that was not previously possible. Here, we critically review several existing biophysical techniques compatible with SMALPs, with a focus on hydrodynamic analysis, microcalorimetric analysis and optical spectroscopic techniques.
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3
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Yang Z, Muccio DD, Melo N, Atigadda VR, Renfrow MB. Stability of the Retinoid X Receptor-α Homodimer in the Presence and Absence of Rexinoid and Coactivator Peptide. Biochemistry 2021; 60:1165-1177. [PMID: 33792309 PMCID: PMC9949482 DOI: 10.1021/acs.biochem.0c00865] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Differential scanning calorimetry and differential scanning fluorimetry were used to measure the thermal stability of human retinoid X receptor-α ligand binding domain (RXRα LBD) homodimer in the absence or presence of rexinoid and coactivator peptide, GRIP-1. The apo-RXRα LBD homodimer displayed a single thermal unfolding transition with a Tm of 58.7 °C and an unfolding enthalpy (ΔH) of 673 kJ/mol (12.5 J/g), much lower than average value (35 J/g) of small globular proteins. Using a heat capacity change (ΔCp) of 15 kJ/(mol K) determined by measurements at different pH values, the free energy of unfolding (ΔG) of the native state was 33 kJ/mol at 37 °C. Rexinoid binding to the apo-homodimer increased Tm by 5 to 9 °C and increased the ΔG of the native homodimer by 12 to 20 kJ/mol at 37 °C, consistent with the nanomolar dissociation constant (Kd) of the rexinoids. GRIP-1 binding to holo-homodimers containing rexinoid resulted in additional increases in ΔG of 14 kJ/mol, a value that was the same for all three rexinoids. Binding of rexinoid and GRIP-1 resulted in a combined 50% increase in unfolding enthalpy, consistent with reduced structural fluidity and more compact folding observed in other published structural studies. The complexes of UAB110 and UAB111 are each more stable than the UAB30 complex by 8 kJ/mol due to enhanced hydrophobic interactions in the binding pocket because of their larger end groups. This increase in thermodynamic stability positively correlates with their improved RXR activation potency. Thermodynamic measurements are thus valuable in predicting agonist potency.
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Affiliation(s)
- Zhengrong Yang
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Donald D. Muccio
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Nathalia Melo
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Venkatram R. Atigadda
- Department of Dermatology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Matthew B. Renfrow
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
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4
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Van Gelder K, Rea KA, Virta LKA, Whitnell KL, Osborn M, Vatta M, Khozin A, Skorupinska-Tudek K, Surmacz L, Akhtar TA. Medium-Chain Polyprenols Influence Chloroplast Membrane Dynamics in Solanum lycopersicum. PLANT & CELL PHYSIOLOGY 2018; 59:2350-2365. [PMID: 30192960 DOI: 10.1093/pcp/pcy157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/31/2018] [Indexed: 06/08/2023]
Abstract
The widespread occurrence of polyprenols throughout the plant kingdom is well documented, yet their functional role is poorly understood. These lipophilic compounds are known to be assembled from isoprenoid precursors by a class of enzymes designated as cis-prenyltransferases (CPTs), which are encoded by small CPT gene families in plants. In this study, we report that RNA interference (RNAi)-mediated knockdown of one member of the tomato CPT family (SlCPT5) reduced polyprenols in leaves by about 70%. Assays with recombinant SlCPT5 produced in Escherichia coli determined that the enzyme synthesizes polyprenols of approximately 50-55 carbons (Pren-10, Pren-11) in length and accommodates a variety of trans-prenyldiphosphate precursors as substrates. Introduction of SlCPT5 into the polyprenol-deficient yeast Δrer2 mutant resulted in the accumulation of Pren-11 in yeast cells, restored proper protein N-glycosylation and rescued the temperature-sensitive growth phenotype that is associated with its polyprenol deficiency. Subcellular fractionation studies together with in vivo localization of SlCPT5 fluorescent protein fusions demonstrated that SlCPT5 resides in the chloroplast stroma and that its enzymatic products accumulate in both thylakoid and envelope membranes. Transmission electron microscopy images of polyprenol-deficient leaves revealed alterations in chloroplast ultrastructure, and anisotropy measurements revealed a more disordered state of their envelope membranes. In polyprenol-deficient leaves, CO2 assimilation was hindered and their thylakoid membranes exhibited lower phase transition temperatures and calorimetric enthalpies, which coincided with a decreased photosynthetic electron transport rate. Taken together, these results uncover a role for polyprenols in governing chloroplast membrane dynamics.
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Affiliation(s)
- Kristen Van Gelder
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kevin A Rea
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Lilia K A Virta
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kenna L Whitnell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Michael Osborn
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Maritza Vatta
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Alexandra Khozin
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | | | - Liliana Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw, Poland
| | - Tariq A Akhtar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
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5
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Wolfe AJ, Gugel JF, Chen M, Movileanu L. Kinetics of Membrane Protein-Detergent Interactions Depend on Protein Electrostatics. J Phys Chem B 2018; 122:9471-9481. [PMID: 30251852 DOI: 10.1021/acs.jpcb.8b07889] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Interactions of a membrane protein with a detergent micelle represent a fundamental process with practical implications in structural and chemical biology. Quantitative assessment of the kinetics of protein-detergent complex (PDC) interactions has always been challenged by complicated behavior of both membrane proteins and solubilizing detergents in aqueous phase. Here, we show the kinetic reads of the desorption of maltoside-containing detergents from β-barrel membrane proteins. Using steady-state fluorescence polarization (FP) anisotropy measurements, we recorded real-time, specific signatures of the PDC interactions. The results of these measurements were used to infer the model-dependent rate constants of association and dissociation of the proteomicelles. Remarkably, the kinetics of the PDC interactions depend on the overall protein charge despite the nonionic nature of the detergent monomers. In the future, this approach might be employed for high-throughput screening of kinetic fingerprints of different membrane proteins stabilized in micelles that contain mixtures of various detergents.
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Affiliation(s)
- Aaron J Wolfe
- Department of Physics , Syracuse University , 201 Physics Building , Syracuse , New York 13244-1130 , United States.,Structural Biology, Biochemistry, and Biophysics Program , Syracuse University , 111 College Place , Syracuse , New York 13244-4100 , United States
| | - Jack F Gugel
- Department of Physics , Syracuse University , 201 Physics Building , Syracuse , New York 13244-1130 , United States
| | - Min Chen
- Department of Chemistry , University of Massachusetts , 820 LGRT, 710 North Pleasant Street , Amherst , Massachusetts 01003-9336 , United States
| | - Liviu Movileanu
- Department of Physics , Syracuse University , 201 Physics Building , Syracuse , New York 13244-1130 , United States.,Structural Biology, Biochemistry, and Biophysics Program , Syracuse University , 111 College Place , Syracuse , New York 13244-4100 , United States.,Department of Biomedical and Chemical Engineering , Syracuse University , 223 Link Hall , Syracuse , New York 13244 , United States
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6
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Ireland SM, Sula A, Wallace B. Thermal melt circular dichroism spectroscopic studies for identifying stabilising amphipathic molecules for the voltage-gated sodium channel NavMs. Biopolymers 2018; 109:e23067. [PMID: 28925040 PMCID: PMC6175354 DOI: 10.1002/bip.23067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/17/2017] [Accepted: 08/23/2017] [Indexed: 11/10/2022]
Abstract
Purified integral membrane proteins require amphipathic molecules to maintain their solubility in aqueous solutions. These complexes, in turn, are used in studies to characterise the protein structures by a variety of biophysical and structural techniques, including spectroscopy, crystallography, and cryo-electron microscopy. Typically the amphilphiles used have been detergent molecules, but more recently they have included amphipols, which are polymers of different sizes and compositions designed to create smaller, more well-defined solubilised forms of the membrane proteins. In this study we used circular dichroism spectroscopy to compare the secondary structures and thermal stabilities of the NavMs voltage-gated sodium channel in different amphipols and detergents as a means of identifying amphipathic environments that maximally maintain the protein structure whilst providing a stabilising environment. These types of characterisations also have potential as means of screening for sample types that may be more suitable for crystallisation and/or cryo-electron microscopy structure determinations.
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Affiliation(s)
- Sam M. Ireland
- Institute of Structural and Molecular Biology, Birkbeck College, University of LondonLondonUnited Kingdom
| | - Altin Sula
- Institute of Structural and Molecular Biology, Birkbeck College, University of LondonLondonUnited Kingdom
| | - B.A. Wallace
- Institute of Structural and Molecular Biology, Birkbeck College, University of LondonLondonUnited Kingdom
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7
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Wolfe AJ, Gugel JF, Chen M, Movileanu L. Detergent Desorption of Membrane Proteins Exhibits Two Kinetic Phases. J Phys Chem Lett 2018; 9:1913-1919. [PMID: 29595981 PMCID: PMC5908730 DOI: 10.1021/acs.jpclett.8b00549] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Gradual dissociation of detergent molecules from water-insoluble membrane proteins culminates in protein aggregation. However, the time-dependent trajectory of this process remains ambiguous because the signal-to-noise ratio of most spectroscopic and calorimetric techniques is drastically declined by the presence of protein aggregates in solution. We show that by using steady-state fluorescence polarization (FP) spectroscopy the dissociation of the protein-detergent complex (PDC) can be inspected in real time at detergent concentrations below the critical micelle concentration. This article provides experimental evidence of the coexistence of two distinct phases of the dissociations of detergent monomers from membrane proteins. We first noted a slow detergent predesolvation process, which was accompanied by a relatively modest change in the FP anisotropy, suggesting a small number of dissociated detergent monomers from the proteomicelles. This predesolvation phase was followed by a fast detergent desolvation process, which was highlighted by a major alteration in the FP anisotropy. The durations and rates of these phases were dependent on both the detergent concentration and the interfacial PDC interactions. Further development of this approach might lead to the creation of a new semiquantitative method for the assessment of the kinetics of association and dissociation of proteomicelles.
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Affiliation(s)
- Aaron J. Wolfe
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
| | - Jack F. Gugel
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Min Chen
- Department of Chemistry, University of Massachusetts Amherst, 820 LGRT, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse University, 223 Link Hall, Syracuse, New York 13244, USA
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8
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Yang Z, Hildebrandt E, Jiang F, Aleksandrov AA, Khazanov N, Zhou Q, An J, Mezzell AT, Xavier BM, Ding H, Riordan JR, Senderowitz H, Kappes JC, Brouillette CG, Urbatsch IL. Structural stability of purified human CFTR is systematically improved by mutations in nucleotide binding domain 1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1193-1204. [PMID: 29425673 DOI: 10.1016/j.bbamem.2018.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 01/19/2018] [Accepted: 02/05/2018] [Indexed: 12/17/2022]
Abstract
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is an ABC transporter containing two transmembrane domains forming a chloride ion channel, and two nucleotide binding domains (NBD1 and NBD2). CFTR has presented a formidable challenge to obtain monodisperse, biophysically stable protein. Here we report a comprehensive study comparing effects of single and multiple NBD1 mutations on stability of both the NBD1 domain alone and on purified full length human CFTR. Single mutations S492P, A534P, I539T acted additively, and when combined with M470V, S495P, and R555K cumulatively yielded an NBD1 with highly improved structural stability. Strategic combinations of these mutations strongly stabilized the domain to attain a calorimetric Tm > 70 °C. Replica exchange molecular dynamics simulations on the most stable 6SS-NBD1 variant implicated fluctuations, electrostatic interactions and side chain packing as potential contributors to improved stability. Progressive stabilization of NBD1 directly correlated with enhanced structural stability of full-length CFTR protein. Thermal unfolding of the stabilized CFTR mutants, monitored by changes in intrinsic fluorescence, demonstrated that Tm could be shifted as high as 67.4 °C in 6SS-CFTR, more than 20 °C higher than wild-type. H1402S, an NBD2 mutation, conferred CFTR with additional thermal stability, possibly by stabilizing an NBD-dimerized conformation. CFTR variants with NBD1-stabilizing mutations were expressed at the cell surface in mammalian cells, exhibited ATPase and channel activity, and retained these functions to higher temperatures. The capability to produce enzymatically active CFTR with improved structural stability amenable to biophysical and structural studies will advance mechanistic investigations and future cystic fibrosis drug development.
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Affiliation(s)
- Zhengrong Yang
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ellen Hildebrandt
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA
| | - Fan Jiang
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - Andrei A Aleksandrov
- Department of Biochemistry and Biophysics and Cystic Fibrosis Treatment and Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Netaly Khazanov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Qingxian Zhou
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jianli An
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Andrew T Mezzell
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - Bala M Xavier
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA
| | - Haitao Ding
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - John R Riordan
- Department of Biochemistry and Biophysics and Cystic Fibrosis Treatment and Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hanoch Senderowitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - John C Kappes
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA; Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, AL 35233, USA
| | | | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA.
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9
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Wolfe AJ, Si W, Zhang Z, Blanden AR, Hsueh YC, Gugel JF, Pham B, Chen M, Loh SN, Rozovsky S, Aksimentiev A, Movileanu L. Quantification of Membrane Protein-Detergent Complex Interactions. J Phys Chem B 2017; 121:10228-10241. [PMID: 29035562 DOI: 10.1021/acs.jpcb.7b08045] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although fundamentally significant in structural, chemical, and membrane biology, the interfacial protein-detergent complex (PDC) interactions have been modestly examined because of the complicated behavior of both detergents and membrane proteins in aqueous phase. Membrane proteins are prone to unproductive aggregation resulting from poor detergent solvation, but the participating forces in this phenomenon remain ambiguous. Here, we show that using rational membrane protein design, targeted chemical modification, and steady-state fluorescence polarization spectroscopy, the detergent desolvation of membrane proteins can be quantitatively evaluated. We demonstrate that depleting the detergent in the sample well produced a two-state transition of membrane proteins between a fully detergent-solvated state and a detergent-desolvated state, the nature of which depended on the interfacial PDC interactions. Using a panel of six membrane proteins of varying hydrophobic topography, structural fingerprint, and charge distribution on the solvent-accessible surface, we provide direct experimental evidence for the contributions of the electrostatic and hydrophobic interactions to the protein solvation properties. Moreover, all-atom molecular dynamics simulations report the major contribution of the hydrophobic forces exerted at the PDC interface. This semiquantitative approach might be extended in the future to include studies of the interfacial PDC interactions of other challenging membrane protein systems of unknown structure. This would have practical importance in protein extraction, solubilization, stabilization, and crystallization.
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Affiliation(s)
- Aaron J Wolfe
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States.,Structural Biology, Biochemistry, and Biophysics Program, Syracuse University , 111 College Place, Syracuse, New York 13244-4100, United States
| | - Wei Si
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University , Nanjing 210096, China.,Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Zhengqi Zhang
- Department of Chemistry and Biochemistry, University of Delaware , 136 Brown Laboratory, Newark, Delaware 19716, United States
| | - Adam R Blanden
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University , 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, United States
| | - Yi-Ching Hsueh
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States
| | - Jack F Gugel
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States
| | - Bach Pham
- Department of Chemistry, University of Massachusetts , 820 LGRT, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, United States
| | - Min Chen
- Department of Chemistry, University of Massachusetts , 820 LGRT, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, United States
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University , 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry, University of Delaware , 136 Brown Laboratory, Newark, Delaware 19716, United States
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Liviu Movileanu
- Department of Physics, Syracuse University , 201 Physics Building, Syracuse, New York 13244-1130, United States.,Structural Biology, Biochemistry, and Biophysics Program, Syracuse University , 111 College Place, Syracuse, New York 13244-4100, United States.,Department of Biomedical and Chemical Engineering, Syracuse University , 329 Link Hall, Syracuse, New York 13244, United States
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10
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Veith K, Martinez Molledo M, Almeida Hernandez Y, Josts I, Nitsche J, Löw C, Tidow H. Lipid-like Peptides can Stabilize Integral Membrane Proteins for Biophysical and Structural Studies. Chembiochem 2017; 18:1735-1742. [PMID: 28603929 PMCID: PMC5601290 DOI: 10.1002/cbic.201700235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Indexed: 12/30/2022]
Abstract
A crucial bottleneck in membrane protein structural biology is the difficulty in identifying a detergent that can maintain the stability and functionality of integral membrane proteins (IMPs). Detergents are poor membrane mimics, and their common use in membrane protein crystallography may be one reason for the challenges in obtaining high-resolution crystal structures of many IMP families. Lipid-like peptides (LLPs) have detergent-like properties and have been proposed as alternatives for the solubilization of G protein-coupled receptors and other membrane proteins. Here, we systematically analyzed the stabilizing effect of LLPs on integral membrane proteins of different families. We found that LLPs could significantly stabilize detergent-solubilized IMPs in vitro. This stabilizing effect depended on the chemical nature of the LLP and the intrinsic stability of a particular IMP in the detergent. Our results suggest that screening a subset of LLPs is sufficient to stabilize a particular IMP, which can have a substantial impact on the crystallization and quality of the crystal.
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Affiliation(s)
- Katharina Veith
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Maria Martinez Molledo
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| | - Yasser Almeida Hernandez
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Inokentijs Josts
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Julius Nitsche
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetScheeles väg 217177StockholmSweden
| | - Henning Tidow
- The Hamburg Centre for Ultrafast ImagingDepartment of ChemistryInstitute for Biochemistry and Molecular BiologyUniversity of HamburgMartin-Luther-King-Platz 620146HamburgGermany
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11
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Wolfe AJ, Hsueh YC, Blanden AR, Mohammad MM, Pham B, Thakur AK, Loh SN, Chen M, Movileanu L. Interrogating Detergent Desolvation of Nanopore-Forming Proteins by Fluorescence Polarization Spectroscopy. Anal Chem 2017; 89:8013-8020. [PMID: 28650154 PMCID: PMC5558884 DOI: 10.1021/acs.analchem.7b01339] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Understanding how membrane proteins interact with detergents is of fundamental and practical significance in structural and chemical biology as well as in nanobiotechnology. Current methods for inspecting protein-detergent complex (PDC) interfaces require high concentrations of protein and are of low throughput. Here, we describe a scalable, spectroscopic approach that uses nanomolar protein concentrations in native solutions. This approach, which is based on steady-state fluorescence polarization (FP) spectroscopy, kinetically resolves the dissociation of detergents from membrane proteins and protein unfolding. For satisfactorily solubilizing detergents, at concentrations much greater than the critical micelle concentration (CMC), the fluorescence anisotropy was independent of detergent concentration. In contrast, at detergent concentrations comparable with or below the CMC, the anisotropy readout underwent a time-dependent decrease, showing a specific and sensitive protein unfolding signature. Functionally reconstituted membrane proteins into a bilayer membrane confirmed predictions made by these FP-based determinations with respect to varying refolding conditions. From a practical point of view, this 96-well analytical approach will facilitate a massively parallel assessment of the PDC interfacial interactions under a fairly broad range of micellar and environmental conditions. We expect that these studies will potentially accelerate research in membrane proteins pertaining to their extraction, solubilization, stabilization, and crystallization, as well as reconstitution into bilayer membranes.
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Affiliation(s)
- Aaron J. Wolfe
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
| | - Yi-Ching Hsueh
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Adam R. Blanden
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, USA
| | - Mohammad M. Mohammad
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Bach Pham
- Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, USA
| | - Avinash K. Thakur
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
| | - Stewart N. Loh
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 4249 Weiskotten Hall, 766 Irving Av., Syracuse, New York 13210, USA
| | - Min Chen
- Department of Chemistry, University of Massachusetts Amherst, 710 North Pleasant Street, Amherst, Massachusetts 01003-9336, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, New York 13244, USA
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12
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Elberson BW, Whisenant TE, Cortes DM, Cuello LG. A cost-effective protocol for the over-expression and purification of fully-functional and more stable Erwinia chrysanthemi ligand-gated ion channel. Protein Expr Purif 2017; 133:177-186. [PMID: 28279818 DOI: 10.1016/j.pep.2017.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/21/2017] [Accepted: 03/04/2017] [Indexed: 10/20/2022]
Abstract
The Erwinia chrysanthemi ligand-gated ion channel, ELIC, is considered an excellent structural and functional surrogate for the whole pentameric ligand-gated ion channel family. Despite its simplicity, ELIC is structurally capable of undergoing ligand-dependent activation and a concomitant desensitization process. To determine at the molecular level the structural changes underlying ELIC's function, it is desirable to produce large quantities of protein. This protein should be properly folded, fully-functional and amenable to structural determinations. In the current paper, we report a completely new protocol for the expression and purification of milligram quantities of fully-functional, more stable and crystallizable ELIC. The use of an autoinduction media and inexpensive detergents during ELIC extraction, in addition to the high-quality and large quantity of the purified channel, are the highlights of this improved biochemical protocol.
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Affiliation(s)
- Benjamin W Elberson
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6551, Lubbock, TX 79430, USA
| | - Ty E Whisenant
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6551, Lubbock, TX 79430, USA
| | - D Marien Cortes
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6551, Lubbock, TX 79430, USA
| | - Luis G Cuello
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6551, Lubbock, TX 79430, USA.
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13
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Yang Z, Zhou Q, Mok L, Singh A, Swartz DJ, Urbatsch IL, Brouillette CG. Interactions and cooperativity between P-glycoprotein structural domains determined by thermal unfolding provides insights into its solution structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:48-60. [PMID: 27783926 DOI: 10.1016/j.bbamem.2016.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/19/2016] [Accepted: 10/21/2016] [Indexed: 12/16/2022]
Abstract
Structural changes in mouse P-glycoprotein (Pgp) induced by thermal unfolding were studied by differential scanning calorimetry (DSC), circular dichroism and fluorescence spectroscopy to gain insight into the solution conformation(s) of this ABC transporter that may not be apparent from current crystal structures. DSC of reconstituted Pgp showed two thermal unfolding transitions in the absence of MgATP, suggesting that each transition involved the cooperative unfolding of two or more interacting structural domains. A low calorimetric unfolding enthalpy and minimal structural changes were observed, which are hallmarks of the thermal unfolding of α-helical membrane proteins, because generally only the extramembranous regions undergo significant unfolding. Nucleotide binding increased the unfolding temperature of both transitions to the same extent, suggesting that one nucleotide binding domain (NBD) unfolds with each transition. Combined with the results from the two isolated NBDs, we propose that each DSC transition represents the cooperative unfolding of one NBD and the two contacting intracellular loops. Further, the presence of two transitions in both apo and MgATP bound wild-type Pgp suggests the NBD-dimeric conformation is transient, and that Pgp resides predominantly in the crystallographically observed inward-facing conformation with NBDs separated, even under conditions supporting continuous MgATP hydrolysis. In contrast, DSC of the vanadate-trapped MgADP·Pgp complex and the MgATP-bound catalytically inactive mutant, E552A/E1197A, show an additional transition at much higher temperature, corresponding to the unfolding of the nucleotide-trapped NBD-dimeric outward-facing conformation. The collective results indicate a strong preference for an NBD dissociated, inward-facing conformation of Pgp.
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Affiliation(s)
- Zhengrong Yang
- Center for Structural Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Qingxian Zhou
- Center for Structural Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Leo Mok
- Department of Cell Biology and Biochemistry, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Anukriti Singh
- Department of Cell Biology and Biochemistry, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Douglas J Swartz
- Department of Cell Biology and Biochemistry, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Christie G Brouillette
- Center for Structural Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA.
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