1
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Hoppenreijs LJG, Annibal A, Vreeke GJC, Boom RM, Keppler JK. Food proteins from yeast-based precision fermentation: Simple purification of recombinant β-lactoglobulin using polyphosphate. Food Res Int 2024; 176:113801. [PMID: 38163711 DOI: 10.1016/j.foodres.2023.113801] [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: 09/18/2023] [Revised: 11/23/2023] [Accepted: 12/02/2023] [Indexed: 01/03/2024]
Abstract
Proteins produced through precision fermentation are often purified through chromatographic methods. Faster and more cost-effective purification methods are desired for food application. Here, we present a simple method for purification of protein produced from yeast, using β-lactoglobulin secreted from Pichia pastoris as an example. The food-grade salt hexametaphosphate (HMP) was used to precipitate the protein at acidic pH, while the impurities (extracellular polysaccharides; mainly mannan) remained soluble. After re-solubilization of the protein-HMP complex by neutralization, excess HMP was selectively precipitated using calcium chloride. The protein content of the crude sample increased from 26 to 72 wt% (comparable to purification with anion exchange chromatography), containing only residual extracellular polysaccharides (9 wt%) and HMP (1 wt%). The established method had no significant impact on the structural and functional properties (i.e., ability to form emulsions) of the protein. The presented method shows potential for cost-effective purification of recombinant proteins produced through yeast-based expression systems.
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Affiliation(s)
- L J G Hoppenreijs
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - A Annibal
- Formo Bio GmbH, Weismüllerstraße 50, 60314 Frankfurt am Main, Germany
| | - G J C Vreeke
- Laboratory of Food Chemistry, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - R M Boom
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands
| | - J K Keppler
- Laboratory of Food Process Engineering, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands.
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2
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Madsen M, Prestel A, Madland E, Westh P, Tøndervik A, Sletta H, Peters GHJ, Aachmann FL, Kragelund BB, Svensson B. Molecular insights into alginate β-lactoglobulin A multivalencies-The foundation for their amorphous aggregates and coacervation. Protein Sci 2023; 32:e4556. [PMID: 36571497 PMCID: PMC9847093 DOI: 10.1002/pro.4556] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/06/2022] [Accepted: 12/22/2022] [Indexed: 12/27/2022]
Abstract
For improved control of biomaterial property design, a better understanding of complex coacervation involving anionic polysaccharides and proteins is needed. Here, we address the initial steps in condensate formation of β-lactoglobulin A (β-LgA) with nine defined alginate oligosaccharides (AOSs) and describe their multivalent interactions in structural detail. Binding of AOSs containing four, five, or six uronic acid residues (UARs), either all mannuronate (M), all guluronate (G), or alternating M and G embodying the block structural components of alginates, was characterized by isothermal titration calorimetry, nuclear magnetic resonance spectroscopy (NMR), and molecular docking. β-LgA was highly multivalent exhibiting binding stoichiometries decreasing from five to two AOSs with increasing degree of polymerization (DP) and similar affinities in the mid micromolar range. The different AOS binding sites on β-LgA were identified by NMR chemical shift perturbation analyses and showed diverse compositions of charged, polar and hydrophobic residues. Distinct sites for the shorter AOSs merged to accommodate longer AOSs. The AOSs bound dynamically to β-LgA, as concluded from saturation transfer difference and 1 H-ligand-targeted NMR analyses. Molecular docking using Glide within the Schrödinger suite 2016-1 revealed the orientation of AOSs to only vary slightly at the preferred β-LgA binding site resulting in similar XP glide scores. The multivalency coupled with highly dynamic AOS binding with lack of confined conformations in the β-LgA complexes may help explain the first steps toward disordered β-LgA alginate coacervate structures.
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Affiliation(s)
- Mikkel Madsen
- Enzyme and Protein Chemistry, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Andreas Prestel
- Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagen NDenmark
| | - Eva Madland
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food ScienceNTNU Norwegian University of Science and TechnologyTrondheimNorway
| | - Peter Westh
- Interfacial Enzymology, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Anne Tøndervik
- Department of Biotechnology and Nanomedicine, SINTEF IndustryTrondheimNorway
| | - Håvard Sletta
- Department of Biotechnology and Nanomedicine, SINTEF IndustryTrondheimNorway
| | - Günther H. J. Peters
- Biophysical and Biomedicinal Chemistry, Department of ChemistryTechnical University of DenmarkKgs. LyngbyDenmark
| | - Finn L. Aachmann
- Norwegian Biopolymer Laboratory (NOBIPOL), Department of Biotechnology and Food ScienceNTNU Norwegian University of Science and TechnologyTrondheimNorway
| | - Birthe B. Kragelund
- Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagen NDenmark
| | - Birte Svensson
- Enzyme and Protein Chemistry, Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
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3
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Castillo O, Mancillas J, Hughes W, Brancaleon L. Characterization of the interaction of metal-protoporphyrins photosensitizers with β- lactoglobulin. Biophys Chem 2023; 292:106918. [PMID: 36399946 DOI: 10.1016/j.bpc.2022.106918] [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: 07/26/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 11/17/2022]
Abstract
We investigated the interaction of a series of metal-protoporphyrins (PPIXs) with bovine β- lactoglobulin (BLG) using a combination of optical spectroscopy and computational simulations. Unlike other studies, the simulations were not merely used to rationalize the experimental data but were employed to refine the experimental data itself. The study was carried out at two pH values, 5 and 9, where BLG is known to have different conformation dictated by the so-called Tanford transition which occurs near pH 7.5. The transition is postulated to regulate access to the interior binding cavity of the protein, thus the pH variation was used as a parameter to investigate whether PPIXs access the central cavity of BLG. The results of our study show that indeed binding increases significantly at alkaline pH, however, the increased affinity is not due to the accessibility of the central cavity. Instead, binding appears to be determined by the tendency of PPIXs to form large inhomogeneous aggregates at acidic pH which hinders interactions with proteins. The binding site determined through a combination of experimental and computational methods is located at the interface between two BLG monomers where the long α-helix segment of the protein face each other. This region is rich in positively charged Lys residues that interact with the propionic acid chains of the protoporphyrins. Establishing the modality of binding between protoporphyrins and BLG would have important consequences for the use of BLG:PPIX complexes in applications such as artificial photoreceptors, artificial metallo-enzymes, delivery of photosensitizers for phototherapy and even solar energy conversion.
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Affiliation(s)
- Omar Castillo
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - James Mancillas
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - William Hughes
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Lorenzo Brancaleon
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249, USA.
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4
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Kieserling H, Giefer P, Uttinger MJ, Lautenbach V, Nguyen T, Sevenich R, Lübbert C, Rauh C, Peukert W, Fritsching U, Drusch S, Maria Wagemans A. Structure and adsorption behavior of high hydrostatic pressure-treated β-lactoglobulin. J Colloid Interface Sci 2021; 596:173-183. [PMID: 33839350 DOI: 10.1016/j.jcis.2021.03.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/24/2021] [Accepted: 03/09/2021] [Indexed: 12/18/2022]
Abstract
HYPOTHESIS High hydrostatic pressure treatment causes structural changes in interfacial-active β-lactoglobulin (β-lg). We hypothesized that the pressure-induced structural changes affect the intra- and intermolecular interactions which determine the interfacial activity of β-lg. The conducted experimental and numerical investigations could contribute to the mechanistic understanding of the adsorption behavior of proteins in food-related emulsions. EXPERIMENTS We treated β-lg in water at pH 7 with high hydrostatic pressures up to 600 MPa for 10 min at 20 °C. The secondary structure was characterized with Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD), the surface hydrophobicity and charge with fluorescence-spectroscopy and ζ-potential, and the quaternary structure with membrane-osmometry, analytical ultracentrifugation (AUC) and mass spectrometry (MS). Experimental analyses were supported through molecular dynamic (MD) simulations. The adsorption behavior was investigated with pendant drop analysis. FINDINGS MD simulation revealed a pressure-induced molten globule state of β-lg, confirmed by an unfolding of β-sheets with FTIR, a stabilization of α-helices with CD and loss in tertiary structure induced by an increase in surface hydrophobicity. Membrane-osmometry, AUC and MS indicated the formation of non-covalently linked dimers that migrated slower through the water phase, adsorbed more quickly due to hydrophobic interactions with the oil, and lowered the interfacial tension more strongly than reference β-lg.
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Affiliation(s)
- Helena Kieserling
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Patrick Giefer
- Leibniz Institute for Materials Engineering-IWT, Particles and Process Engineering, Badgasteiner Str. 3, 28359 Bremen, Germany.
| | - Maximilian J Uttinger
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Vanessa Lautenbach
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Thu Nguyen
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Robert Sevenich
- Technische Universität Berlin, Department of Food Biotechnology and Process Engineering, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Christian Lübbert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Cornelia Rauh
- Technische Universität Berlin, Department of Food Biotechnology and Process Engineering, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Wolfgang Peukert
- Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Haberstrasse 9a, 91058 Erlangen, Germany.
| | - Udo Fritsching
- Leibniz Institute for Materials Engineering-IWT, Particles and Process Engineering, Badgasteiner Str. 3, 28359 Bremen, Germany; University of Bremen, Particles and Process Engineering, Bibliothekstraße 1, 28359 Bremen, Germany.
| | - Stephan Drusch
- Technische Universität Berlin, Department of Food Technology and Food Material Science, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Anja Maria Wagemans
- Technische Universität Berlin, Department of Food Colloids, Straße des 17. Juni 135, 10623 Berlin, Germany.
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5
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Darmawan KK, Karagiannis TC, Hughes JG, Small DM, Hung A. In silico modelling of apo-lactoferrin under simulated gastric conditions: Structural dynamics, binding with β-lactoglobulin and α-lactalbumin, and functional implications. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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6
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Dynamic adsorption and interfacial rheology of whey protein isolate at oil-water interfaces: Effects of protein concentration, pH and heat treatment. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2021.106640] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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7
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Kieserling H, Pankow A, Keppler JK, Wagemans AM, Drusch S. Conformational state and charge determine the interfacial film formation and film stability of β-lactoglobulin. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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8
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Naso JN, Bellesi FA, Pizones Ruiz-Henestrosa VM, Pilosof AMR. A new methodology to assess the solubility of fatty acids: Impact of food emulsifiers. Food Res Int 2021; 139:109829. [PMID: 33509455 DOI: 10.1016/j.foodres.2020.109829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 11/17/2022]
Abstract
In food formulations, lipids are normally incorporated as emulsions stabilized by different types of emulsifiers. The emulsifiers can affect fatty acid (FA) solubilization as they can interact with FA. The main purpose of the present work is the development of a methodology to evaluate the FA solubilization in an aqueous medium in the absence and presence of exogenous emulsifiers. To this end, a combination of turbidimetry, oiling off and dynamic light scattering (DLS) was used. The FA solubility, as well as its supramolecular assemblies, were determined by analyzing the changes in the turbidity profile and the corresponding size of particles obtained by DLS. Oleic acid (OA) was used as a model FA and a simulated intestinal fluid (SIF) as the aqueous phase. Emulsifiers of low (Tween 80) and high (protein and polysaccharide) molecular weight were tested. Tween 80 was the only emulsifier that improved OA solubilization, whereas the macromolecules only affected the supramolecular structure that OA adopted, being the structure of these assemblies governed by the emulsifier nature.
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Affiliation(s)
- Julieta N Naso
- ITAPROQ - Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires, Argentina; Fellowship Agencia Nacional de Promoción Científica y Tecnológica, Argentina
| | - Fernando A Bellesi
- ITAPROQ - Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Víctor M Pizones Ruiz-Henestrosa
- ITAPROQ - Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Ana M R Pilosof
- ITAPROQ - Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
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9
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Bello M. Structural mechanism of the Tanford transition of bovine β-lactoglobulin through microsecond molecular dynamics simulations. J Biomol Struct Dyn 2020; 40:3011-3023. [PMID: 33155532 DOI: 10.1080/07391102.2020.1844062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
X-ray analysis has provided structural data about a pH-driven conformational change in β-lactoglobulin (BLG) known as the Tanford transition, which occurs at around pH 7 and involves the EF loop, which acts as a lid closing the internal cavity of the protein below pH 7 and opening it above pH 7. NMR studies using wild-type BLG have encountered problems trying to explain the Tanford transition, however, they have provided important insight using a dimeric BLG mutant, revealing that the opening and closure of the EF loop consists of two types of motions in the microsecond and milliseconds timescales. This provides valuable information indicating that the dimeric state is a good model to study the Tanford transition, although the understanding of this structural change is still lacking at the atomic level. We performed microsecond molecular dynamics (MD) simulations starting from different conformations of BLG in the monomeric and dimeric state, with protonated and deprotonated E89, in order to explore the Tanford transition. Our results provide structural information for the transition from the closed to the open conformation in BLG and show it occurs in the dimeric state in the microsecond timescale, in line with the fast motion observed through NMR experiments. In addition, MD simulations coupled to MMGBSA approach indicated that the most populated conformer of BLG in the open state is able to bind ligands with similar affinity to that of BLG at neutral pH obtained through crystallographic experiments.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Martiniano Bello
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
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10
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Changes in the molecular structure and stability of β-lactoglobulin induced by heating with sugar beet pectin in the dry-state. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Zhu J, Li K, Wu H, Li W, Sun Q. Multi-spectroscopic, conformational, and computational atomic-level insights into the interaction of β-lactoglobulin with apigenin at different pH levels. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105810] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Bonarek P, Loch JI, Tworzydło M, Cooper DR, Milto K, Wróbel P, Kurpiewska K, Lewiński K. Structure-based design approach to rational site-directed mutagenesis of β-lactoglobulin. J Struct Biol 2020; 210:107493. [PMID: 32169624 DOI: 10.1016/j.jsb.2020.107493] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/06/2020] [Accepted: 03/09/2020] [Indexed: 12/30/2022]
Abstract
Recombinant proteins play an important role in medicine and have diverse applications in industrial biotechnology. Lactoglobulin has shown great potential for use in targeted drug delivery and body fluid detoxification because of its ability to bind a variety of molecules. In order to modify the biophysical properties of β-lactoglobulin, a series of single-site mutations were designed using a structure-based approach. A 3-dimensional structure alignment of homologous molecules led to the design of nine β-lactoglobulin variants with mutations introduced in the binding pocket region. Seven stable and correctly folded variants (L39Y, I56F, L58F, V92F, V92Y, F105L, M107L) were thoroughly characterized by fluorescence, circular dichroism, isothermal titration calorimetry, size-exclusion chromatography, and X-ray structural investigations. The effects of the amino acid substitutions were observed as slight rearrangements of the binding pocket geometry, but they also significantly influenced the global properties of the protein. Most of the mutations increased the thermal/chemical stability without altering the dimerization constant or pH-dependent conformational behavior. The crystal structures reveal that the I56F and F105L mutations reduced the depth of the binding pocket, which is advantageous since it can reduce the affinity to endogenous fatty acids. The F105L mutant created a unique binding mode for a fatty acid, supporting the idea that lactoglobulin can be altered to bind unique molecules. Selected variants possessing a unique combination of their individual properties can be used for further, more advanced mutagenesis, and the presented results support further research using β-lactoglobulin as a therapeutic delivery agent or a blood detoxifying molecule.
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Affiliation(s)
- Piotr Bonarek
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - Joanna I Loch
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Magdalena Tworzydło
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - David R Cooper
- University of Virginia, Department of Molecular Physiology and Biological Physics, 1340 Jefferson Park Avenue, Charlottesville, VA 22908, USA
| | - Katažyna Milto
- Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Gronostajowa 7, 30-387 Kraków, Poland
| | - Paulina Wróbel
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Katarzyna Kurpiewska
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland
| | - Krzysztof Lewiński
- Jagiellonian University, Faculty of Chemistry, Gronostajowa 2, 30-387 Kraków, Poland.
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13
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Chen X, Zhang H, Hemar Y, Li N, Zhou P. Glycerol induced stability enhancement and conformational changes of β-lactoglobulin. Food Chem 2020; 308:125596. [DOI: 10.1016/j.foodchem.2019.125596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 11/26/2022]
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14
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Brotzakis ZF, Bolhuis PG. Unbiased Atomistic Insight into the Mechanisms and Solvent Role for Globular Protein Dimer Dissociation. J Phys Chem B 2019; 123:1883-1895. [PMID: 30714378 PMCID: PMC6581425 DOI: 10.1021/acs.jpcb.8b10005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/30/2019] [Indexed: 12/18/2022]
Abstract
Association and dissociation of proteins are fundamental processes in nature. Although simple to understand conceptually, the details of the underlying mechanisms and role of the solvent are poorly understood. Here, we investigate the dissociation of the hydrophilic β-lactoglobulin dimer by employing transition path sampling. Analysis of the sampled path ensembles reveals a variety of mechanisms: (1) a direct aligned dissociation (2) a hopping and rebinding transition followed by unbinding, and (3) a sliding transition before unbinding. Reaction coordinate and transition-state analysis predicts that, besides native contact and neighboring salt-bridge interactions, solvent degrees of freedom play an important role in the dissociation process. Bridging waters, hydrogen-bonded to both proteins, support contacts in the native state and nearby lying transition-state regions, whereas they exhibit faster dynamics in further lying transition-state regions, rendering the proteins more mobile and assisting in rebinding. Analysis of the structure and dynamics of the solvent molecules reveals that the dry native interface induces enhanced populations of both disordered hydration water near hydrophilic residues and tetrahedrally ordered hydration water nearby hydrophobic residues. Although not exhaustive, our sampling of rare unbiased reactive molecular dynamics trajectories enhances the understanding of protein dissociation via complex pathways including (multiple) rebinding events.
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Affiliation(s)
| | - P. G. Bolhuis
- Van’t Hoff Institute
for Molecular Sciences, Universiteit van
Amsterdam, Science Park 904, 1090 GD Amsterdam, The Netherlands
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15
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Conformational state and charge determine the interfacial stabilization process of beta-lactoglobulin at preoccupied interfaces. J Colloid Interface Sci 2019; 536:300-309. [DOI: 10.1016/j.jcis.2018.10.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 01/19/2023]
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16
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Świątek S, Komorek P, Turner G, Jachimska B. β-Lactoglobulin as a potential carrier for bioactive molecules. Bioelectrochemistry 2018; 126:137-145. [PMID: 30590224 DOI: 10.1016/j.bioelechem.2018.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 12/18/2022]
Abstract
In this study, the interaction and binding behavior of anesthetic tetracaine (TET) with bovine β-lactoglobulin (LGB) isoform A and a mixture of isoforms A and B were investigated under varying environmental conditions (pH, ionic strength, concentration, LGB-TET complex molar ratio). A wide range of analytical techniques (dynamic light scattering (DLS), electrophoretic mobility, UV-Vis spectroscopy, circular dichroism (CD), quartz crystal microbalance (QCM-D) were used to analyze the physicochemical properties of the complexes in bulk solution and on the surface of gold. The experiments revealed that TET, which is amphiphilic, could bind with LGB not only in the β-barrel but also onto the surface. The zeta potential of the LGB becomes more positively charged upon interaction with TET due to electrostatic interaction of the amino group present in the TET structure. Changes in the zeta potential values are mostly visible above pH 6 for all tested systems. CD spectra show that interaction with the ligand does not change the secondary structure of the protein. The physicochemical properties of LGB-TET complex were examined in an adsorbed state on a gold surface using the QCM-D method. Additionally, molecular docking was used to evaluate the most likely binding site for TET with LGB.
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Affiliation(s)
- S Świątek
- Polish Academy of Sciences, Jerzy Haber Institute of Catalysis and Surface Chemistry, Niezapominajek 8, Cracow 30-239, Poland
| | - P Komorek
- Polish Academy of Sciences, Jerzy Haber Institute of Catalysis and Surface Chemistry, Niezapominajek 8, Cracow 30-239, Poland
| | - G Turner
- Department of Chemical and Process Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow, UK
| | - B Jachimska
- Polish Academy of Sciences, Jerzy Haber Institute of Catalysis and Surface Chemistry, Niezapominajek 8, Cracow 30-239, Poland.
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17
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Felce JH, Sezgin E, Wane M, Brouwer H, Dustin ML, Eggeling C, Davis SJ. CD45 exclusion- and cross-linking-based receptor signaling together broaden FcεRI reactivity. Sci Signal 2018; 11:11/561/eaat0756. [PMID: 30563863 DOI: 10.1126/scisignal.aat0756] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
For many years, the high-affinity receptor for immunoglobulin E (IgE) FcεRI, which is expressed by mast cells and basophils, has been widely held to be the exemplar of cross-linking (that is, aggregation dependent) signaling receptors. We found, however, that FcεRI signaling could occur in the presence or absence of receptor cross-linking. Using both cell and cell-free systems, we showed that FcεRI signaling was stimulated by surface-associated monovalent ligands through the passive, size-dependent exclusion of the receptor-type tyrosine phosphatase CD45 from plasma membrane regions of FcεRI-ligand engagement. Similarly to the T cell receptor, FcεRI signaling could also be initiated in a ligand-independent manner. These data suggest that a simple mechanism of CD45 exclusion-based receptor triggering could function together with cross-linking-based FcεRI signaling, broadening mast cell and basophil reactivity by enabling these cells to respond to both multivalent and surface-presented monovalent antigens. These findings also strengthen the case that a size-dependent, phosphatase exclusion-based receptor triggering mechanism might serve generally to facilitate signaling by noncatalytic immune receptors.
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Affiliation(s)
- James H Felce
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK.,Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Erdinc Sezgin
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Madina Wane
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Heather Brouwer
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK.
| | - Christian Eggeling
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Simon J Davis
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK. .,Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
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18
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Suzuki R, Sakakura M, Mori M, Fujii M, Akashi S, Takahashi H. Methyl-selective isotope labeling using α-ketoisovalerate for the yeast Pichia pastoris recombinant protein expression system. JOURNAL OF BIOMOLECULAR NMR 2018; 71:213-223. [PMID: 29869771 DOI: 10.1007/s10858-018-0192-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Methyl-detected NMR spectroscopy is a useful tool for investigating the structures and interactions of large macromolecules such as membrane proteins. The procedures for preparation of methyl-specific isotopically-labeled proteins were established for the Escherichia coli (E. coli) expression system, but typically it is not feasible to express eukaryotic proteins using E. coli. The Pichia pastoris (P. pastoris) expression system is the most common yeast expression system, and is known to be superior to the E. coli system for the expression of mammalian proteins, including secretory and membrane proteins. However, this system has not yet been optimized for methyl-specific isotope labeling, especially for Val/Leu-methyl specific isotope incorporation. To overcome this difficulty, we explored various culture conditions for the yeast cells to efficiently uptake Val/Leu precursors. Among the searched conditions, we found that the cultivation pH has a critical effect on Val/Leu precursor uptake. At an acidic cultivation pH, the uptake of the Val/Leu precursor was increased, and methyl groups of Val and Leu in the synthesized recombinant protein yielded intense 1H-13C correlation signals. Based on these results, we present optimized protocols for the Val/Leu-methyl-selective 13C incorporation by the P. pastoris expression system.
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Affiliation(s)
- Rika Suzuki
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Masayoshi Sakakura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Masaki Mori
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Moe Fujii
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Satoko Akashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Hideo Takahashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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19
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Sengupta B, Das N, Sen P. Monomerization and aggregation of β-lactoglobulin under adverse condition: A fluorescence correlation spectroscopic investigation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:316-326. [DOI: 10.1016/j.bbapap.2017.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 11/01/2017] [Accepted: 11/12/2017] [Indexed: 12/26/2022]
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20
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Jachimska B, Świątek S, Loch JI, Lewiński K, Luxbacher T. Adsorption effectiveness of β-lactoglobulin onto gold surface determined by quartz crystal microbalance. Bioelectrochemistry 2018; 121:95-104. [PMID: 29413868 DOI: 10.1016/j.bioelechem.2018.01.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/20/2017] [Accepted: 01/22/2018] [Indexed: 12/30/2022]
Abstract
Bovine β-lactoglobulin (LGB) is a transport protein that can bind to its structure hydrophobic bioactive molecules. Due to the lack of toxicity, high stability and pH-dependent molecular binding mechanism, lactoglobulin can be used as a carrier of sparingly soluble drugs. Dynamic light scattering has confirmed LGB's tendency to create oligomeric forms. The hydrodynamic diameter of LGB molecules varies from 4 nm to 6 nm in the pH range of 2-10 and ionic strength I = 0.001-0.15 M, which corresponds to the presence of mono or dimeric LGB forms. The LGB zeta potential varies from 26.5 mV to -33.3 mV for I = 0.01 M and from 13.3 mV to -16 mV for I = 0.15 M in the pH range of 2-10. The isoelectric point is at pH 4.8. As a result of strong surface charge compensation, the maximum effective ionization degree of the LGB molecule is 35% for ionic strength I = 0.01 M and 22% for I = 0.15 M. The effectiveness of adsorption is linked with the properties of the protein, as well as those of the adsorption surface. The functionalization of gold surfaces with β-lactoglobulin (LGB) was studied using a quartz crystal microbalance with energy dissipation monitoring (QCM-D). The effectiveness of LGB adsorption correlates strongly with a charge of gold surface and the zeta potential of the molecule. The greatest value of the adsorbed mass was observed in the pH range in which LGB has a positive zeta potential values, below pH 4.8. This observation shows that electrostatic interactions play a dominant role in LGB adsorption on gold surfaces. Based on the adsorbed mass, protein orientation on gold surfaces was determined. The preferential side-on orientation of LGB molecules observed in the adsorption layer is consistent with the direction of the molecule dipole momentum determined by molecular dynamics simulations of the protein (MD). The use of the QCM-D method also allowed us to determine the effectiveness of adsorption of LGB on gold surface. Knowing the mechanism of LGB adsorption is significant importance for determining the optimum conditions for immobilizing this protein on solid surfaces. As β-lactoglobulin is a protein that binds various ligands, the binding properties of immobilized β-lactoglobulin can be used to design controlled protein structures for biomedical applications.
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Affiliation(s)
- B Jachimska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, PAS, Niezapominajek 8, 30-239 Cracow, Poland.
| | - S Świątek
- Jerzy Haber Institute of Catalysis and Surface Chemistry, PAS, Niezapominajek 8, 30-239 Cracow, Poland
| | - J I Loch
- Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Biocrystallography Group, Ingardena 3, 30-060 Cracow, Poland
| | - K Lewiński
- Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Biocrystallography Group, Ingardena 3, 30-060 Cracow, Poland
| | - T Luxbacher
- Anton Paar GmbH, Anton-Paar-Strasse 20, 8045 Graz, Austria
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21
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Palanisamy D, Pandiyan BV, Duraisamy T, Kolandaivel P. Understanding the potency of fatty acids with the amino acid side chains of bovine β lactoglobulin—A quantum chemical approach. J Mol Graph Model 2017; 74:105-116. [DOI: 10.1016/j.jmgm.2017.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/11/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
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22
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Brotzakis ZF, Bolhuis PG. A one-way shooting algorithm for transition path sampling of asymmetric barriers. J Chem Phys 2016; 145:164112. [DOI: 10.1063/1.4965882] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Z. Faidon Brotzakis
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
| | - Peter G. Bolhuis
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands
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23
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Bello M, Fragoso-Vázquez MJ, Correa Basurto J. Energetic and conformational features linked to the monomeric and dimeric states of bovine BLG. Int J Biol Macromol 2016; 92:625-636. [PMID: 27456117 DOI: 10.1016/j.ijbiomac.2016.07.071] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 07/15/2016] [Accepted: 07/21/2016] [Indexed: 11/16/2022]
Abstract
Bovine β-lactoglobulin (BLG) belong to the lipocalin family. This is a group of proteins involved in the binding and transporting of hydrophobic molecules. Experimental and theoretical reports have stated its complex structural behavior in solution, with coupled effects between homodimerization and ligand recognition. Nonetheless, structural evidence at the atomic level about the cause of this coupled effect has not been reported to date. To address this issue microsecond molecular dynamics (MD) simulations were combined with the molecular mechanics generalized Born surface area (MM/GBSA) approach, clustering analysis and principal component analysis (PCA), to explore the conformational complexity of BLG protein-protein self-association and palmitic acid (PLM) or dodecyl sulfate (SDS) ligand recognition in the monomeric and dimeric state. MD simulations, coupled to the MM/GBSA method, revealed that dimerization exerts contrasting effects on the ligand-binding capacity of BLG. Protein dimerization decreases PLM affinity, promoting dimer association. For SDS the dimeric state increases affinity, enhancing dimer dissociation. MD simulations based on PCA revealed that while few differences in the conformational subspace are observed between the free and bound monomer and dimer coupling for PLM, substantial changes are observed between the free and bound monomer and dimer coupling for SDS.
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Affiliation(s)
- Martiniano Bello
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis Y Diaz Mirón S/N, Col. Casco de Santo Tomas, Mexico City CP: 11340, Mexico.
| | - M Jonathan Fragoso-Vázquez
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis Y Diaz Mirón S/N, Col. Casco de Santo Tomas, Mexico City CP: 11340, Mexico
| | - José Correa Basurto
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis Y Diaz Mirón S/N, Col. Casco de Santo Tomas, Mexico City CP: 11340, Mexico
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24
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Hadian M, Hosseini SMH, Farahnaky A, Mesbahi GR, Yousefi GH, Saboury AA. Isothermal titration calorimetric and spectroscopic studies of β-lactoglobulin-water-soluble fraction of Persian gum interaction in aqueous solution. Food Hydrocoll 2016. [DOI: 10.1016/j.foodhyd.2015.11.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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25
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Bello M. Structural and energetic requirements for a second binding site at the dimeric β-lactoglobulin interface. J Biomol Struct Dyn 2016; 34:1884-902. [DOI: 10.1080/07391102.2015.1094413] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Martiniano Bello
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos de la Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis Y Diaz Mirón S/N, Col. Casco de Santo Tomas, CP 11340 México, D. F., Mexico
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26
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Chen J, Kong Y, Wo Y, Fang H, Li Y, Zhang T, Dong Y, Ge Y, Wu Z, Zhou D, Chen S. Facile synthesis of β-lactoglobulin capped Ag2S quantum dots for in vivo imaging in the second near-infrared biological window. J Mater Chem B 2016; 4:6271-6278. [PMID: 32263639 DOI: 10.1039/c6tb01186a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Effectivein vivofluorescence imaging based on β-LG-Ag2S quantum dots at the second near-infrared region.
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27
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Abstract
Lipocalins are one of the most important groups of inhalant animal allergens. The analysis of structural features of these proteins is important to get insights into their allergenicity. We have determined two different dimeric crystal structures for bovine dander lipocalin Bos d 2, which was earlier described as a monomeric allergen. The crystal structure analysis of all other determined lipocalin allergens also revealed oligomeric structures which broadly utilize inherent structural features of the β-sheet in dimer formation. According to the moderate size of monomer-monomer interfaces, most of these dimers would be transient in solution. Native mass spectrometry was employed to characterize quantitatively transient dimerization of two lipocalin allergens, Bos d 2 and Bos d 5, in solution.
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28
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Blake S, Amin S, Qi W, Majumdar M, Lewis EN. Colloidal Stability & Conformational Changes in β-Lactoglobulin: Unfolding to Self-Assembly. Int J Mol Sci 2015; 16:17719-33. [PMID: 26247930 PMCID: PMC4581217 DOI: 10.3390/ijms160817719] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 11/16/2022] Open
Abstract
A detailed understanding of the mechanism of unfolding, aggregation, and associated rheological changes is developed in this study for β-Lactoglobulin at different pH values through concomitant measurements utilizing dynamic light scattering (DLS), optical microrheology, Raman spectroscopy, and differential scanning calorimetry (DSC). The diffusion interaction parameter kD emerges as an accurate predictor of colloidal stability for this protein consistent with observed aggregation trends and rheology. Drastic aggregation and gelation were observed at pH 5.5. Under this condition, the protein's secondary and tertiary structures changed simultaneously. At higher pH (7.0 and 8.5), oligomerizaton with no gel formation occurred. For these solutions, tertiary structure and secondary structure transitions were sequential. The low frequency Raman data, which is a good indicator of hydrogen bonding and structuring in water, has been shown to exhibit a strong correlation with the rheological evolution with temperature. This study has, for the first time, demonstrated that this low frequency Raman data, in conjunction with the DSC endotherm, can be been utilized to deconvolve protein unfolding and aggregation/gelation. These findings can have important implications for the development of protein-based biotherapeutics, where the formulation viscosity, aggregation, and stability strongly affects efficacy or in foods where protein structuring is critical for functional and sensory performance.
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Affiliation(s)
- Steven Blake
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Samiul Amin
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Wei Qi
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - Madhabi Majumdar
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
| | - E Neil Lewis
- Malvern Instruments, 7221 Lee Deforest Drive, Suite 300, Columbia, MD 21046, USA.
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29
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Hosseini SMH, Emam-Djomeh Z, Sabatino P, Van der Meeren P. Nanocomplexes arising from protein-polysaccharide electrostatic interaction as a promising carrier for nutraceutical compounds. Food Hydrocoll 2015. [DOI: 10.1016/j.foodhyd.2015.04.006] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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30
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Sakurai K, Nakahata R, Lee YH, Kardos J, Ikegami T, Goto Y. Effects of a reduced disulfide bond on aggregation properties of the human IgG1 CH3 domain. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1526-35. [PMID: 25748879 DOI: 10.1016/j.bbapap.2015.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/13/2015] [Accepted: 02/26/2015] [Indexed: 10/23/2022]
Abstract
Recombinant human monoclonal antibodies have become important protein-based therapeutics for the treatment of various diseases. An IgG1 molecule, which is now mainly used for antibody preparation, consists of a total of 12 immunoglobulin domains. Each domain has one disulfide bond. The CH3 domain is the C-terminal domain of the heavy chain of IgG1. The disulfide bonds of some of the CH3 domains are known to be reduced in recombinant human monoclonal antibodies. The lack of intramolecular disulfide bonds may decrease the stability and increase the aggregation propensity of an antibody molecule. To investigate the effects of a reduced disulfide bond in the CH3 domain on conformational stability and aggregation propensity, we performed several physicochemical measurements including circular dichroism, differential scanning calorimetry (DSC), and 2D NMR. DSC measurements showed that both the stability and reversibility of the reduced form were lower than those of the oxidized form. In addition, detailed analyses of the thermal denaturation data revealed that, although a dominant fraction of the reduced form retained a stable dimeric structure, some fractions assumed a less-specifically associated oligomeric state between monomers. The results of the present study revealed the characteristic aggregation properties of antibody molecules.
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Affiliation(s)
- Kazumasa Sakurai
- High Pressure Protein Research Center, Institute of Advanced Technology, Kinki University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan; Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
| | - Ryosuke Nakahata
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Young-Ho Lee
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - József Kardos
- Department of Biochemistry, Eötvös Loránd University, Pázmány P. sétány 1/C, Budapest, H-1117 Hungary; MTA-ELTE NAP B Neuroimmunology Research Group, Eötvös Loránd University, Pázmány P. sétány 1/C, Budapest, H-1117 Hungary
| | - Takahisa Ikegami
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yuji Goto
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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31
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Kontopidis G, Nordle Gilliver A, Sawyer L. Ovine β-lactoglobulin at atomic resolution. Acta Crystallogr F Struct Biol Commun 2014; 70:1498-503. [PMID: 25372816 PMCID: PMC4231851 DOI: 10.1107/s2053230x14020950] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 09/19/2014] [Indexed: 11/10/2022] Open
Abstract
The crystal structure of the triclinic form of the milk protein β-lactoglobulin from sheep (Ovis aries) at 1.1 Å resolution is described together with a comparison of the triclinic structures of the low-pH bovine and high-pH ovine proteins. All three structures are remarkably similar, despite the well known pH-dependent conformational transition described for the bovine and porcine proteins that occurs in solution. The high resolution of the present structure determination has allowed a more accurate description of the protein than has hitherto been possible, but it is still not clear whether flexibility changes in the external loops can compensate for the presence of a significant void in the unliganded interior of the structure.
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Affiliation(s)
- George Kontopidis
- Structural Biochemistry Group, Institute of Cell and Molecular Biology, The University of Edinburgh, Swann Building, King’s Buildings, Mayfield Road, Edinburgh EH10 3BF, Scotland
| | - Anna Nordle Gilliver
- Structural Biochemistry Group, Institute of Cell and Molecular Biology, The University of Edinburgh, Swann Building, King’s Buildings, Mayfield Road, Edinburgh EH10 3BF, Scotland
| | - Lindsay Sawyer
- Structural Biochemistry Group, Institute of Cell and Molecular Biology, The University of Edinburgh, Swann Building, King’s Buildings, Mayfield Road, Edinburgh EH10 3BF, Scotland
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32
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Ma B, You X, Lu F. Inhibitory effects of β-ionone on amyloid fibril formation of β-lactoglobulin. Int J Biol Macromol 2014; 64:162-7. [DOI: 10.1016/j.ijbiomac.2013.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/09/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
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33
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马 保. Dithiothreitol Inhibits the Amyloid Fibril Formation of β-Lactoglobulin. Biophysics (Nagoya-shi) 2014. [DOI: 10.12677/biphy.2014.24005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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34
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Nucara A, Maselli P, Giliberti V, Carbonaro M. Epicatechin-induced conformational changes in β-lactoglobulin B monitored by FT-IR spectroscopy. SPRINGERPLUS 2013; 2:661. [PMID: 24353978 PMCID: PMC3866372 DOI: 10.1186/2193-1801-2-661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/12/2013] [Indexed: 12/31/2022]
Abstract
ABSTRACT The interaction between whey carrier protein β-lactoglobulin B and (-)-epicatechin, a major dietary flavonoid with a wide range of health-promoting biological activities, was investigated by Fourier transform infrared spectroscopy in physiological conditions. Amide I spectra of epicatechin - β-lactoglobulin complexes, in D2O buffer solutions, pD= 6.8, at molar ratios from 0.5:1 to 15:1, were measured by using a cell device specifically created. Changes in secondary structure elements at increasing epicatechin concentrations were quantified. Two different trends were observed for the intensities of β-sheet, random coil, and side chain contributions. At molar ratios ≤2 the β-exposed strand contributions (1625 cm(-1)) increased at the expence of the β-antiparallel sheet band (1637 cm(-1)). At molar ratios >2 the intensities of both β structures slightly decreased. The same behaviour was observed for the side chain contributions (band around 1610 ÷ 1620 cm(-1)). In addition, a conformational transition to a slightly opened structure, followed by aggregate formation at the highest molar ratios, were revealed. The results suggest that binding of epicatechin to β-lactoglobulin in physiological conditions occurs at the surface of the protein molecule, resulting in protein dissociation at molar ratios ≤2 with minor changes in secondary structure. This finding provides further evidence for the possibility of successful use of the protein as a carrier of flavonoids, epicatechin included.
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Affiliation(s)
- Alessandro Nucara
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
| | - Paola Maselli
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
| | - Valeria Giliberti
- CNR-Istituto di Fotonica e Nanotecnologie, Via Cineto Romano 42, 00156 Rome, Italy
| | - Marina Carbonaro
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy
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35
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Chen HL, Cao MJ, Cai QF, Su WJ, Mao HY, Liu GM. Purification and characterisation of sarcoplasmic calcium-binding protein, a novel allergen of red swamp crayfish (Procambarus clarkii). Food Chem 2013; 139:213-23. [DOI: 10.1016/j.foodchem.2013.01.119] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/23/2012] [Accepted: 01/29/2013] [Indexed: 10/27/2022]
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36
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Binding of 18-carbon unsaturated fatty acids to bovine β-lactoglobulin—Structural and thermodynamic studies. Int J Biol Macromol 2013; 57:226-31. [DOI: 10.1016/j.ijbiomac.2013.03.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/06/2013] [Accepted: 03/08/2013] [Indexed: 11/19/2022]
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37
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Macromolecular crowding modulates the kinetics and morphology of amyloid self-assembly by β-lactoglobulin. Int J Biol Macromol 2013; 53:82-7. [DOI: 10.1016/j.ijbiomac.2012.11.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/03/2012] [Accepted: 11/05/2012] [Indexed: 11/19/2022]
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38
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Kurylowicz M, Giuliani M, Dutcher JR. Using nanoscale substrate curvature to control the dimerization of a surface-bound protein. ACS NANO 2012; 6:10571-10580. [PMID: 23136964 DOI: 10.1021/nn302948d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of surface geometry on adsorbed proteins offers new possibilities for controlling quaternary structure by manipulating protein-protein interactions at a surface, with applications that are relevant to protein aggregation, fibrillation, ligand binding, and surface catalysis. To understand the effect of surface curvature on the structure of the surface-bound protein β-lactoglobulin (β-LG), we have used a combination of polystyrene (PS) nanoparticles (NPs) and ultrathin PS films to fabricate chemically pure, hydrophobic surfaces that have nanoscale curvature and are stable in aqueous buffer. We have used single molecule force spectroscopy to measure the detachment contour lengths L(c) for β-LG adsorbed on the highly curved PS surfaces, and we compare these values in situ to those measured for β-LG adsorbed on flat PS surfaces on the same samples. The L(c) distributions measured on all flat PS surfaces show a large monomer peak near 60 nm and a smaller dimer peak at 120 nm. For 190 and 100 nm diameter NPs, which are effectively flat on the scale of the β-LG molecules, there is no measurable difference between the L(c) distributions obtained for the flat and curved surfaces. However, for 60 nm diameter NPs the dimer peak is smaller, and for 25 nm diameter NPs the dimer peak is absent, indicating that the number of surface-bound dimers is significantly reduced by an increase in the curvature of the underlying surface. These results indicate that surface curvature provides a new method of manipulating protein-protein interactions and controlling the quaternary structure of adsorbed proteins.
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Affiliation(s)
- Martin Kurylowicz
- Department of Physics, University of Guelph, Guelph ON, Canada N1G 2W1
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Adel-Patient K, Nutten S, Bernard H, Fritsché R, Ah-Leung S, Meziti N, Prioult G, Mercenier A, Wal JM. Immunomodulatory potential of partially hydrolyzed β-lactoglobulin and large synthetic peptides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:10858-10866. [PMID: 23043375 DOI: 10.1021/jf3031293] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The immunomodulatory potential of fragments derived from the cow's milk allergen bovine β-lactoglobulin (BLG) was assessed in a mouse model of oral tolerance (OT) [Adel-Patient, K.; Wavrin, S.; Bernard, H.; Meziti, N.; Ah-Leung, S.; Wal, J. M. Oral tolerance and Treg cells are induced in BALB/c mice after gavage with bovine β-lactoglobulin. Allergy 2011, 66 (10), 1312-1321]. Native BLG (nBLG) and chemically denatured BLG (lacking S-S bridges, dBLG), products resulting from their hydrolysis using cyanogen bromide (CNBr) and some synthetic peptides, were produced and precisely characterized. CNBr hydrolysates correspond to pools of peptides of various sizes that are still associated by S-S bridges when derived from nBLG. nBLG, dBLG, and CNBr hydrolysate of nBLG efficiently prevented further sensitization. CNBr hydrolysate of dBLG was less efficient, suggesting that the association by S-S bridges of peptides increased their immunomodulatory potential. Conversely, synthetic peptides were inefficient even if covering 50% of the BLG sequence, demonstrating that the immunomodulatory potential requires the presence of all derived fragments of BLG and further supporting the use of partially hydrolyzed milk proteins to favor OT induction in infants with a risk of atopy.
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Affiliation(s)
- Karine Adel-Patient
- INRA, UR496 Immuno-Allergie Alimentaire, CEA/IBiTeC-S/SPI, CEA de Saclay, F-91191 Gif sur Yvette cedex, France.
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40
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Legg-E’Silva D, Achilonu I, Fanucchi S, Stoychev S, Fernandes M, Dirr HW. Role of Arginine 29 and Glutamic Acid 81 Interactions in the Conformational Stability of Human Chloride Intracellular Channel 1. Biochemistry 2012; 51:7854-62. [DOI: 10.1021/bi300874b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Derryn Legg-E’Silva
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Ikechukwu Achilonu
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Sylvia Fanucchi
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Stoyan Stoychev
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Manuel Fernandes
- School of
Chemistry, University of the Witwatersrand, Johannesburg 2050,
South Africa
| | - Heini W. Dirr
- Protein Structure−Function
Research Unit, School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg 2050,
South Africa
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Mercadante D, Melton LD, Norris GE, Loo TS, Williams MAK, Dobson RCJ, Jameson GB. Bovine β-lactoglobulin is dimeric under imitative physiological conditions: dissociation equilibrium and rate constants over the pH range of 2.5-7.5. Biophys J 2012; 103:303-12. [PMID: 22853908 DOI: 10.1016/j.bpj.2012.05.041] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 05/03/2012] [Accepted: 05/15/2012] [Indexed: 10/28/2022] Open
Abstract
The oligomerization of β-lactoglobulin (βLg) has been studied extensively, but with somewhat contradictory results. Using analytical ultracentrifugation in both sedimentation equilibrium and sedimentation velocity modes, we studied the oligomerization of βLg variants A and B over a pH range of 2.5-7.5 in 100 mM NaCl at 25°C. For the first time, to our knowledge, we were able to estimate rate constants (k(off)) for βLg dimer dissociation. At pH 2.5 k(off) is low (0.008 and 0.009 s(-1)), but at higher pH (6.5 and 7.5) k(off) is considerably greater (>0.1 s(-1)). We analyzed the sedimentation velocity data using the van Holde-Weischet method, and the results were consistent with a monomer-dimer reversible self-association at pH 2.5, 3.5, 6.5, and 7.5. Dimer dissociation constants K(D)(2-1) fell close to or within the protein concentration range of ∼5 to ∼45 μM, and at ∼45 μM the dimer predominated. No species larger than the dimer could be detected. The K(D)(2-1) increased as |pH-pI| increased, indicating that the hydrophobic effect is the major factor stabilizing the dimer, and suggesting that, especially at low pH, electrostatic repulsion destabilizes the dimer. Therefore, through Poisson-Boltzmann calculations, we determined the electrostatic dimerization energy and the ionic charge distribution as a function of ionic strength at pH above (pH 7.5) and below (pH 2.5) the isoelectric point (pI∼5.3). We propose a mechanism for dimer stabilization whereby the added ionic species screen and neutralize charges in the vicinity of the dimer interface. The electrostatic forces of the ion cloud surrounding βLg play a key role in the thermodynamics and kinetics of dimer association/dissociation.
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Adikaram PR, Beckett D. Functional versatility of a single protein surface in two protein:protein interactions. J Mol Biol 2012; 419:223-33. [PMID: 22446587 DOI: 10.1016/j.jmb.2012.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/12/2012] [Accepted: 03/14/2012] [Indexed: 11/18/2022]
Abstract
The ability of the Escherichia coli protein BirA to function as both a metabolic enzyme and a transcription repressor relies on the use of a single surface for two distinct protein:protein interactions. BirA forms a heterodimer with the biotin acceptor protein of acetyl-coenzyme A carboxylase and catalyzes posttranslational biotinylation. Alternatively, it forms a homodimer that binds sequence-specifically to DNA to repress transcription initiation at the biotin biosynthetic operon. Several surface loops on BirA, two of which exhibit sequence conservation in all biotin protein ligases and the remainder of which are highly variable, are located at the two interfaces. The function of these loops in both homodimerization and biotin transfer was investigated by characterizing alanine-substituted variants at 18 positions of one constant and three variable loops. Sedimentation equilibrium measurements reveal that 11 of the substitutions, which are distributed throughout conserved and variable loops, significantly alter homodimerization energetics. By contrast, steady-state and single-turnover kinetic measurements indicate that biotin transfer to biotin carboxyl carrier protein is impacted by seven substitutions, the majority of which are in the constant loop. Furthermore, constant loop residues that function in biotin transfer also support homodimerization. The results reveal clues about the evolution of a single protein surface for use in two distinct functions.
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Affiliation(s)
- Poorni R Adikaram
- Department of Chemistry and Biochemistry and Center for Biomolecular Structure and Organization, University of Maryland, College Park, MD 20742, USA
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Ohtomo H, Fujiwara K, Ikeguchi M. Important role of methionine 145 in dimerization of bovine -lactoglobulin. J Biochem 2011; 151:329-34. [DOI: 10.1093/jb/mvr142] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Sciuto SV, Liu J, Konermann L. An electrostatic charge partitioning model for the dissociation of protein complexes in the gas phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:1679-1689. [PMID: 21952881 DOI: 10.1007/s13361-011-0205-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 06/27/2011] [Accepted: 06/28/2011] [Indexed: 05/31/2023]
Abstract
Electrosprayed multi-protein complexes can be dissociated by collisional activation in the gas phase. Typically, these processes follow a mechanism whereby a single subunit gets ejected with a disproportionately high amount of charge relative to its mass. This asymmetric behavior suggests that the departing subunit undergoes some degree of unfolding prior to being separated from the residual complex. These structural changes occur concomitantly with charge (proton) transfer towards the subunit that is being unraveled. Charge accumulation takes place up to the point where the subunit loses physical contact with the residual complex. This work develops a simple electrostatic model for studying the relationship between conformational changes and charge enrichment during collisional activation. Folded subunits are described as spheres that carry continuum surface charge. The unfolded chain is envisioned as random coil bead string. Simulations are guided by the principle that the system will adopt the charge configuration with the lowest potential energy for any backbone conformation. A finite-difference gradient algorithm is used to determine the charge on each subunit throughout the dissociation process. Both dimeric and tetrameric protein complexes are investigated. The model reproduces the occurrence of asymmetric charge partitioning for dissociation events that are preceded by subunit unfolding. Quantitative comparisons of experimental MS/MS data with model predictions yield estimates of the structural changes that occur during collisional activation. Our findings suggest that subunit separation can occur over a wide range of scission point structures that correspond to different degrees of unfolding.
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Affiliation(s)
- Stephen V Sciuto
- Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada
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Ohtomo H, Konuma T, Utsunoiya H, Tsuge H, Ikeguchi M. Structure and stability of Gyuba, a β-lactoglobulin chimera. Protein Sci 2011; 20:1867-75. [PMID: 21853497 DOI: 10.1002/pro.720] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/06/2011] [Accepted: 08/09/2011] [Indexed: 11/09/2022]
Abstract
β-lactoglobulin (LG) contains nine β-strands (strands A-I) and one α-helix. Strands A-H form a β-barrel. At neutral pH, equine LG (ELG) is monomeric, whereas bovine LG (BLG) is dimeric, and the I-strands of its two subunits form an intermolecular β-sheet. We previously constructed a chimeric ELG in which the sequence of the I-strand was replaced with that of BLG. This chimera did not dimerize. For this study, we constructed the new chimera we call Gyuba (which means cow and horse in Japanese). The amino acid sequence of Gyuba includes the sequences of the BLG secondary structures and those of the ELG loops. The crystal structure of Gyuba is very similar to that of BLG and indicates that Gyuba dimerizes via the intermolecular β-sheet formed by the two I-strands. Thus, the entire arrangement of the secondary structural elements is important for LG dimer formation.
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Affiliation(s)
- Hideaki Ohtomo
- Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, Japan
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Sakurai K, Fujioka S, Konuma T, Yagi M, Goto Y. A circumventing role for the non-native intermediate in the folding of β-lactoglobulin. Biochemistry 2011; 50:6498-507. [PMID: 21678970 DOI: 10.1021/bi200241a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Folding experiments have suggested that some proteins have kinetic intermediates with a non-native structure. A simple G ̅o model does not explain such non-native intermediates. Therefore, the folding energy landscape of proteins with non-native intermediates should have characteristic properties. To identify such properties, we investigated the folding of bovine β-lactoglobulin (βLG). This protein has an intermediate with a non-native α-helical structure, although its native form is predominantly composed of β-structure. In this study, we prepared mutants whose α-helical and β-sheet propensities are modified and observed their folding using a stopped-flow circular dichroism apparatus. One interesting finding was that E44L, whose β-sheet propensity was increased, showed a folding intermediate with an amount of β-structure similar to that of the wild type, though its folding took longer. Thus, the intermediate seems to be a trapped intermediate. The high α-helical propensity of the wild-type sequence likely causes the folding pathway to circumvent such time-consuming intermediates. We propose that the role of the non-native intermediate is to control the pathway at the beginning of the folding reaction.
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Affiliation(s)
- Kazumasa Sakurai
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Abstract
Beta-lactoglobulin (BLG) is the most prominent allergen causing milk allergy and contains disulfide (S-S) bonds that may be responsible for its allergic action. As S-S bonds may be reduced during electrolysis, this study was undertaken to evaluate modulation of the allergic action of BLG after electrolysis. A current of 85 mA/cm(2) was applied, and the allergic action was evaluated by means of competitive CAP-FEIA inhibition tests and skin prick tests (SPT). Modification of BLG was examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). Although the number of total free sulfhydryl (SH) groups of BLG did not differ between the cathode and anode sides, BLG on the cathode side showed 54% lower inhibition than untreated BLG in the competitive CAP-FEIA inhibition tests, and reduced wheal reactions, by 71%, in the SPT compared with those with untreated BLG. The SPT results with BLG on the anode side did not differ significantly from those with untreated BLG. The MALDI-ToF-MS results for the dimer of untreated BLG or BLG on the anode side showed two distinct peptide fragments (residues (41)V-(60)K and (149)L-(162)I) but, on the contrary, the dimer of BLG on the cathode side did not give these fragments, this being similar to in the case of the monomer of BLG. The allergic action of BLG was markedly mitigated during electrolysis on the cathode side, a dimer of BLG with a different mass spectrometric pattern from that of the dimer of untreated BLG being simultaneously formed.
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Affiliation(s)
- Tomoaki Matsumoto
- Department of Child Development, Graduate School of Life Sciences, School of Medicine, Kumamoto University, Kumamoto, Japan.
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Liu J, Konermann L. Protein-protein binding affinities in solution determined by electrospray mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:408-17. [PMID: 21472560 DOI: 10.1007/s13361-010-0052-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/10/2010] [Accepted: 12/10/2010] [Indexed: 05/23/2023]
Abstract
Electrospray ionization (ESI) allows the transfer of multi-protein complexes into the gas phase, thereby providing a simple approach for monitoring the stoichiometry of these noncovalent assemblies by mass spectrometry (MS). It remains unclear, however, whether the measured ion abundance ratios of free and bound species are suitable for determining solution-phase binding affinities (K(d) values). Many types of mass spectrometers employ rf-only quadrupoles as ion guides. This work demonstrates that the settings used for these devices are a key factor for ensuring uniform transmission behavior, which is a prerequisite for meaningful affinity measurements. Using bovine β-lactoglobulin and hemoglobin as model systems, it is demonstrated that under carefully adjusted conditions the "direct" ESI-MS approach is capable of providing K(d) values that are in good agreement with previously published solution-phase data. Of the several ion sources tested, a regular ESI emitter operated with pressure-driven flow at 1 μL min(-1) provided the most favorable results. Potential problems in these experiments include conformationally-induced differences in ionization efficiencies, inadvertent collision-induced dissociation, and ESI-induced clustering artifacts. A number of simple tests can be conducted to assess whether or not these factors are prevalent under the conditions used. In addition, the fidelity of the method can be scrutinized by performing measurements over a wide concentration range. Overall, this work supports the viability of the direct ESI-MS approach for determining binding affinities of protein-protein complexes in solution.
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Affiliation(s)
- Jiangjiang Liu
- Department of Chemistry, The University of Western Ontario, N6A 5B7 London, Ontario, Canada
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Loch J, Polit A, Górecki A, Bonarek P, Kurpiewska K, Dziedzicka-Wasylewska M, Lewiński K. Two modes of fatty acid binding to bovine β-lactoglobulin-crystallographic and spectroscopic studies. J Mol Recognit 2010; 24:341-9. [DOI: 10.1002/jmr.1084] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 07/28/2010] [Accepted: 07/29/2010] [Indexed: 11/11/2022]
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Rouvinen J, Jänis J, Laukkanen ML, Jylhä S, Niemi M, Päivinen T, Mäkinen-Kiljunen S, Haahtela T, Söderlund H, Takkinen K. Transient dimers of allergens. PLoS One 2010; 5:e9037. [PMID: 20140203 PMCID: PMC2816702 DOI: 10.1371/journal.pone.0009037] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 01/14/2010] [Indexed: 11/21/2022] Open
Abstract
Background Allergen-mediated cross-linking of IgE antibodies bound to the FcεRI receptors on the mast cell surface is the key feature of the type I allergy. If an allergen is a homodimer, its allergenicity is enhanced because it would only need one type of antibody, instead of two, for cross-linking. Methodology/Principal Findings An analysis of 55 crystal structures of allergens showed that 80% of them exist in symmetric dimers or oligomers in crystals. The majority are transient dimers that are formed at high protein concentrations that are reached in cells by colocalization. Native mass spectrometric analysis showed that native allergens do indeed form transient dimers in solution, while hypoallergenic variants of them exist almost solely in the monomeric form. We created a monomeric Bos d 5 allergen and show that it has a reduced capability to induce histamine release. Conclusions/Significance The results suggest that dimerization would be a very common and essential feature for allergens. Thus, the preparation of purely monomeric variants of allergens could open up novel possibilities for specific immunotherapy.
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Affiliation(s)
- Juha Rouvinen
- Department of Chemistry, University of Eastern Finland, Joensuu, Finland.
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