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Nevídalová H, Michalcová L, Glatz Z. Capillary electrophoresis-based approaches for the study of affinity interactions combined with various sensitive and nontraditional detection techniques. Electrophoresis 2019; 40:625-642. [PMID: 30600537 DOI: 10.1002/elps.201800367] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/20/2018] [Accepted: 12/20/2018] [Indexed: 12/17/2022]
Abstract
Nearly all processes in living organisms are controlled and regulated by the synergy of many biomolecule interactions involving proteins, peptides, nucleic acids, nucleotides, saccharides, and small molecular weight ligands. There is growing interest in understanding them, not only for the purposes of interactomics as an essential part of system biology, but also in their further elucidation in disease pathology, diagnostics, and treatment. The necessity of detailed investigation of these interactions leads to the requirement of laboratory methods characterized by high efficiency and sensitivity. As a result, many instrumental approaches differing in their fundamental principles have been developed, including those based on capillary electrophoresis. Although capillary electrophoresis offers numerous advantages for such studies, it still has one serious limitation, its poor concentration sensitivity with the most commonly used detection method-ultraviolet-visible spectrometry. However, coupling capillary electrophoresis with a more sensitive detector fulfils the above-mentioned requirement. In this review, capillary electrophoresis combined with fluorescence, mass spectrometry, and several nontraditional detection techniques in affinity interaction studies are summarized and discussed, together with the possibility of conducting these measurements in microchip format.
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Affiliation(s)
- Hana Nevídalová
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Lenka Michalcová
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Zdeněk Glatz
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
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2
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Abstract
The present review covers recent advances and important applications of affinity capillary electrophoresis (ACE). It provides an overview about various ACE types, including ACE-MS, the multiple injection mode, the use of microchips and field-amplified sample injection-ACE. The most common scenarios of the studied affinity interactions are protein-drug, protein-metal ion, protein-protein, protein-DNA, protein-carbohydrate, carbohydrate-drug, peptide-peptide, DNA-drug and antigen-antibody. Approaches for the improvements of ACE in term of precision, rinsing protocols and sensitivity are discussed. The combined use of computer simulation programs to support data evaluation is presented. In conclusion, the performance of ACE is compared with other techniques such as equilibrium dialysis, parallel artificial membrane permeability assay, high-performance affinity chromatography as well as surface plasmon resonance, ultraviolet, circular dichroism, nuclear magnetic resonance, Fourier transform infrared, fluorescence, MS and isothermal titration calorimetry.
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3
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Wang J, Jin X, Liu J, Khosla C, Xia J. Resolving multiple protein-peptide binding events: implication for HLA-DQ2 mediated antigen presentation in celiac disease. Chem Asian J 2012; 7:992-9. [PMID: 22411856 DOI: 10.1002/asia.201101041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/01/2012] [Indexed: 11/09/2022]
Abstract
Techniques that can effectively separate protein-peptide complexes from free peptides have shown great value in major histocompatibility complex (MHC)-peptide binding studies. However, most of the available techniques are limited to measuring the binding of a single peptide to an MHC molecule. As antigen presentation in vivo involves both endogenous ligands and exogenous antigens, the deconvolution of multiple binding events necessitates the implementation of a more powerful technique. Here we show that capillary electrophoresis coupled to fluorescence detection (CE-FL) can resolve multiple MHC-peptide binding events owing to its superior resolution and the ability to simultaneously monitor multiple emission channels. We utilized CE-FL to investigate competition and displacement of endogenous peptides by an immunogenic gluten peptide for binding to HLA-DQ2. Remarkably, this immunogenic peptide could displace CLIP peptides from the DQ2 binding site at neutral but not acidic pH. This unusual ability of the gluten peptide supports a direct loading mechanism of antigen presentation in extracellular environment, a property that could explain the antigenicity of dietary gluten in celiac disease.
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Affiliation(s)
- Jianhao Wang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, P. R. China
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4
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Xia Z, Li L, Yang J, Xiong C. Investigation of interaction between the drug and cell membrane by capillary electrophoresis. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11426-009-0156-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Justesen S, Harndahl M, Lamberth K, Nielsen LLB, Buus S. Functional recombinant MHC class II molecules and high-throughput peptide-binding assays. Immunome Res 2009; 5:2. [PMID: 19416502 PMCID: PMC2690590 DOI: 10.1186/1745-7580-5-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 05/05/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Molecules of the class II major histocompability complex (MHC-II) specifically bind and present exogenously derived peptide epitopes to CD4+ T helper cells. The extreme polymorphism of the MHC-II hampers the complete analysis of peptide binding. It is also a significant hurdle in the generation of MHC-II molecules as reagents to study and manipulate specific T helper cell responses. Methods to generate functional MHC-II molecules recombinantly, and measure their interaction with peptides, would be highly desirable; however, no consensus methodology has yet emerged. RESULTS We generated alpha and beta MHC-II chain constructs, where the membrane-spanning regions were replaced by dimerization motifs, and the C-terminal of the beta chains was fused to a biotinylation signal peptide (BSP) allowing for in vivo biotinylation. These chains were produced separately as inclusion bodies in E. coli , extracted into urea, and purified under denaturing and non-reducing conditions using conventional column chromatography. Subsequently, diluting the two chains into a folding reaction with appropriate peptide resulted in efficient peptide-MHC-II complex formation. Several different formats of peptide-binding assay were developed including a homogeneous, non-radioactive, high-throughput (HTS) binding assay. Binding isotherms were generated allowing the affinities of interaction to be determined. The affinities of the best binders were found to be in the low nanomolar range. Recombinant MHC-II molecules and accompanying HTS peptide-binding assay were successfully developed for nine different MHC-II molecules including the DPA1*0103/DPB1*0401 (DP401) and DQA1*0501/DQB1*0201, where both alpha and beta chains are polymorphic, illustrating the advantages of producing the two chains separately. CONCLUSION We have successfully developed versatile MHC-II resources, which may assist in the generation of MHC class II -wide reagents, data, and tools.
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Affiliation(s)
- Sune Justesen
- Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
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6
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Analysis of proteins in solution using affinity capillary electrophoresis. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008. [PMID: 18826064 DOI: 10.1007/978-1-59745-582-4_21] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Analysis of protein interactions by means of capillary electrophoresis (CE) has unique challenges and rewards. The choice of analysis conditions, especially involving electrophoresis buffers, are crucial and not universal for protein analysis. If conditions for analysis can be worked out, it is possible to utilize CE quantitatively and qualitatively to characterize protein-ligand binding involving unmodified molecules in solution and taking place under physiological conditions. This chapter deals with the most important practical considerations in capillary electrophoretic affinity approaches, affinity CE (ACE). The text emphasizes the most critical factors for successful analyses and has application examples illustrating various types of information offered by ACE-based studies. Also included are step-by-step accounts of the two main classes of experimental design: the pre-equilibration ACE (in the form of CE-frontal analysis (CE-FA)) and mobility shift ACE together with examples of their use. The ACE approaches for binding assays of proteins should be considered when the biological material is scarce, when any kind of labeling is not possible or desired, when the interacting molecules are the same size and when rapid and simple method development is a priority.
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Zavaleta J, Chinchilla D, Gomez A, Silverio C, Azad M, Gomez FA. On-column ligand/receptor derivatization coupled to affinity capillary electrophoresis. Methods Mol Biol 2008; 384:647-660. [PMID: 18392588 DOI: 10.1007/978-1-59745-376-9_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The coupling of on-column derivatization of small molecules to affinity capillary electrophoresis (ACE) has only been realized during the past 5 yr. In this technique, multiple zones of reagent(s) and ligand or receptor are injected into the capillary column. Upon electrophoresis, zones of sample overlap, yielding product. Continued electrophoresis results in the product overlapping with receptor (or ligand, if the receptor was derivatized), thereby causing a shift in migration time of the compound in question. Subsequent Scatchard analysis using noninteracting standards realizes a binding constant. Herein, we describe the use of on-column-ligand and receptor derivatization coupled to partial-filling ACE (PFACE) to probe the binding of vancomycin (Van) from Streptomyces orientalis and teicoplanin (Teic) from Actinoplanes teicomyceticus to D-Ala-D-Ala terminus peptides.
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Affiliation(s)
- Jose Zavaleta
- California State University, Los Angeles, Los Angeles, CA, USA
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Silverio CF, Plazas A, Moran J, Gomez FA. DETERMINATION OF BINDING CONSTANTS BETWEEN TEICOPLANIN AND D-ALA-D-ALA TERMINUS PEPTIDES BY AFFINITY CAPILLARY ELECTROPHORESIS. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120005714] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- C. F. Silverio
- a Department of Chemistry and Biochemistry , California State University at Los Angeles , 5151 State University Drive, Los Angeles , CA , 90032-8202 , U.S.A
| | - A. Plazas
- a Department of Chemistry and Biochemistry , California State University at Los Angeles , 5151 State University Drive, Los Angeles , CA , 90032-8202 , U.S.A
| | - J. Moran
- a Department of Chemistry and Biochemistry , California State University at Los Angeles , 5151 State University Drive, Los Angeles , CA , 90032-8202 , U.S.A
| | - F. A. Gomez
- a Department of Chemistry and Biochemistry , California State University at Los Angeles , 5151 State University Drive, Los Angeles , CA , 90032-8202 , U.S.A
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9
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Ostergaard J, Heegaard NHH. Bioanalytical interaction studies executed by preincubation affinity capillary electrophoresis. Electrophoresis 2006; 27:2590-608. [PMID: 16732622 DOI: 10.1002/elps.200600047] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The versatility of CE is beneficial for the study of many types of molecular interactions, because different experimental designs can be made to suit the characteristics of a particular interaction. A very versatile starting point is the preequilibration type of affinity CE that has been used extensively for characterizing biomolecular interactions in the last 15 years. We review this field here and include a comprehensive overview of the existing preincubation ACE modes including their advantages and limitations as well as the methodological developments and applications within the bioanalytical field.
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Affiliation(s)
- Jesper Ostergaard
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Copenhagen, Denmark.
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10
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Quaglia M, Carazzone C, Sabella S, Colombo R, Giorgetti S, Bellotti V, De Lorenzi E. Search of ligands for the amyloidogenic protein beta2-microglobulin by capillary electrophoresis and other techniques. Electrophoresis 2005; 26:4055-63. [PMID: 16200532 DOI: 10.1002/elps.200500313] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Beta2-microglobulin (beta2-m) is a small amyloidogenic protein normally present on the surface of most nucleated cells and responsible for dialysis-related amyloidosis, which represents a severe complication of long-term hemodialysis. A therapeutic approach for this amyloidosis could be based on the stabilization of beta2-m through the binding to a small molecule, and consequent inhibition of protein misfolding and amyloid fibril formation. A few compounds have been described to weakly bind beta2-m, including the drug suramin. The lack of a binding site for nonpolypeptidic ligands on the beta2-m structure makes it difficult for both the identification of functional groups responsible for the binding and the search of hits to be optimized. The characterization of the binding properties of suramin for beta2-m by using three different techniques (surface plasmon resonance, affinity CE (ACE), ultrafiltration) is here described and the results obtained are compared. The common features of the chemical structures of the compounds known to bind the protein led us to select 200 sulfonated/suramin-like molecules from a wider chemical library on the basis of similarity rules, so as to possibly single out some interesting hits and to gain more information on the functional groups involved in the binding. The development of screening methods to test the compounds by using ultrafiltration and ACE is described.
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Affiliation(s)
- Milena Quaglia
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Pavia, Italy.
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11
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Azad M, Hernandez L, Plazas A, Rudolph M, Gomez FA. Determination of binding constants between the antibiotic ristocetin A and D-Ala-D-Ala terminus peptides by affinity capillary electrophoresis. Chromatographia 2003. [DOI: 10.1007/bf02492405] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Heegaard NHH, Nissen MH, Chen DDY. Applications of on-line weak affinity interactions in free solution capillary electrophoresis. Electrophoresis 2002; 23:815-22. [PMID: 11920866 DOI: 10.1002/1522-2683(200203)23:6<815::aid-elps815>3.0.co;2-v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g., drug enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On-line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities.
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Affiliation(s)
- Niels H H Heegaard
- Department of Autoimmunology, Bldg. 81, Rm. 536, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
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Heegaard NHH, Kennedy RT. Antigen-antibody interactions in capillary electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 768:93-103. [PMID: 11939562 DOI: 10.1016/s0378-4347(01)00489-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Immunoreactions in combination with separations by capillary electrophoresis (CE) are increasingly being used to quantitate specific analytes in biological fluids. Both competitive and non-competitive approaches have been used for the purpose and, in selected cases, now compare favorably with conventional quantitative immunoassays with respect to concentration limits of detection. CE is also a useful method to evaluate antigen-antibody binding on-line and offers unique possibilities for binding constant estimates, also for weakly binding antibodies and antibody fragments. In this review we cover recent developments in the use of antigen-antibody interactions in conjunction with CE and conclude that continued development of miniaturization, on-line preconcentration and more sensitive detection schemes will contribute to the further dissemination of CE-based immunoassays building on already established affinity CE approaches.
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Affiliation(s)
- Niels H H Heegaard
- Department of Autoimmunology, Statens Serum Institute, Copenhagen, Denmark.
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14
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Abstract
Protein interactions are important in determining the transport, metabolism and/or activity of many chiral compounds within the body. This review examines data that have been obtained on these interactions by various chromatographic and electrophoretic methods, especially those based on either high-performance liquid chromatography or capillary electrophoresis. Zonal elution, frontal analysis and vacancy methods are each considered, as are approaches that employ either soluble or immobilized proteins. There are a variety of different items that can be learned about a solute-protein system through these techniques. This includes information on the binding constants and number of binding sites for a solute-protein system, as well as the thermodynamic parameters, rate constants, interaction forces and binding site structure for the protein and solute. Numerous examples are provided throughout this review, as taken from the literature and from work performed within the author's laboratory.
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Affiliation(s)
- D S Hage
- Department of Chemistry, University of Nebraska--Lincoln, 68588-0304, USA.
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15
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Abstract
Molecular recognition may be characterized both qualitatively and quantitatively by electrophoretic methods if complexed molecules differ in electrophoretic mobility from unbound ones. The use of capillary zone electrophoresis (CE) for the characterization of affinity interactions is advantageous because of the high resolution, reproducibility and wide applicability of the technique and because of the mild conditions, i.e., physiological buffers without additions of organics or detergents, that are often sufficient for highly efficient separations. CE gives the ability to characterize binding between small amounts of unlabelled reactants in solution, has few requirements for special characteristics of the interacting molecules and is also applicable to the study of interactions of individual components in mixtures, as detection of binding and analytical separation are achieved in one step. This is unique compared with other techniques for the study of non-covalent interactions. The advantages and disadvantages of using CE to demonstrate molecular interactions, to screen for specific ligand binding in complex mixtures and to calculate binding constants will be discussed.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark.
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16
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Fürtös-Matei A, Day R, St-Pierre SA, St-Pierre LG, Waldron KC. Micellar electrokinetic chromatography separations of dynorphin peptide analogs. Electrophoresis 2000; 21:715-23. [PMID: 10733211 DOI: 10.1002/(sici)1522-2683(20000301)21:4<715::aid-elps715>3.0.co;2-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Prodynorphin is a precursor that has multiple cleavage sites to release various dynorphin opioid peptides. The dynorphin analogs used in this study have 18 amino acid residues. A series of dynorphin-like peptides, differing by a single residue (alanine substitution) were assembled by Fmoc solid-phase procedures and purified by preparative high performance liquid chromatography (HPLC). Separation of the Ala-scan dynorphin analogs was investigated by micellar electrokinetic chromatography (MEKC) employing anionic, cationic and zwitterionic surfactants. The role of electrostatic and hydrophobic forces in analyte-surfactant interactions is discussed with respect to the observed elution patterns. Separation of all dynorphin analogs by MEKC using a zwitterionic surfactant shows this technique to be powerful for separating closely related peptide species. It also demonstrates the potential for using MEKC for the prescreening of peptide libraries to determine their biological activity toward specific receptors. Results from the separation of dynorphin analogs by free solution and ion-pairing capillary electrophoresis are also presented.
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Affiliation(s)
- A Fürtös-Matei
- Département de Chimie, Université de Montréal, Québec, Canada
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17
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Flow-through partial-filling affinity capillary electrophoresis for the estimation of binding constants of ligands to receptors. Chromatographia 1999. [DOI: 10.1007/bf02497305] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
This review article with 125 references describes recent developments in capillary zone electrophoresis of proteins. It encompasses approximately the last two years, from the previous review (V. Dolník, Electrophoresis 1997, 18, 2353-2361) through Spring 1999. Topics covered include modeling of the electrophoretic properties of proteins, sample preconcentration and derivatization, wall coatings, improving selectivity, special detection techniques, and applications.
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Affiliation(s)
- V Dolník
- Molecular Dynamics, Sunnyvale, CA 94086, USA.
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19
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Heegaard NH, Kennedy RT. Identification, quantitation, and characterization of biomolecules by capillary electrophoretic analysis of binding interactions. Electrophoresis 1999; 20:3122-33. [PMID: 10596820 DOI: 10.1002/(sici)1522-2683(19991001)20:15/16<3122::aid-elps3122>3.0.co;2-m] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The high resolving power of capillary electrophoresis combined with the specificity of binding interactions may be used with advantage to characterize the structure-function relationship of biomolecules, to quantitate specific analytes in complex sample matrices, and to determine the purity of pharmaceutical and other molecules. We here review recent and innovative methodologies and applications of high resolution affinity electrophoresis within the fields of binding constant determination, structure-activity studies, quantitative microassays, analysis of drug purity and protein conformation, and immobilized affinity ligands. Despite the virtues of these approaches with respect to applicability, resolving power, speed, and low sample consumption, problems remain with respect to analyte identification and low concentration limits of detection. The ongoing development of new detector technologies for capillary electrophoresis such as mass spectrometry, and possibly nuclear magnetic resonance and other spectroscopic methods, is therefore very promising for the continued increased use of affinity capillary electrophoresis.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark.
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20
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Abstract
This article gives a review of the recent developments in capillary electrophoresis (CE) of peptides. New approaches to the theoretical description of electromigration behavior of peptides are described, and methodological aspects of CE separations of peptides such as selection of separation conditions, sample treatment, suppression of peptide adsorption to the capillary wall and specificities of CE separation modes are discussed. Progress in application of high performance detection schemes, namely laser-induced fluorescence and mass spectrometry, in peptide separations by CE is presented. Applications of different CE techniques, zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography and electrochromatography to peptide analysis, preparation and physicochemical characterization are demonstrated.
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Affiliation(s)
- V Kasicka
- Institute for Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague.
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21
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Caldwell GW, McDonnell PA, Masucci JA, Johnson DL, Jolliffe LK. Using affinity capillary electrophoresis to study the interaction of the extracellular binding domain of erythropoietin receptor with peptides. JOURNAL OF BIOCHEMICAL AND BIOPHYSICAL METHODS 1999; 40:17-25. [PMID: 10481948 DOI: 10.1016/s0165-022x(99)00011-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have shown that affinity capillary electrophoresis (ACE) can be utilized to screen peptides that bind to the extracellular binding domain of the erythropoietin receptor (EBP). The comparison of the cyclic peptides GGTYSCHFGPLTWVCKPQGG (EMP1) GGTYSCHFGPLTAVCKPQGG (EMP13), and LGRKYSCHFGPLTWVCQPAKKD (EMP37) with the linear peptides HFGPLTWV (EMP26) and FMRF as ACE buffer additives were investigated. When EMP1 and EMP37 were the buffer additives, an abrupt change in the electrophoretic mobility of EBP was observed in the electropherogram. When EMP13, EMP26, and FMRF were examined under identical ACE conditions as EMP1 and EMP37, no significant change in the electrophoretic mobility of EBP was observed. These results correlate well with previously reported IC50 competitive binding data; that is, EMP1 and EMP37 bind to EBP while EMP13 and EMP26 bind very weakly. These observations strongly infer that peptide.EBP dimerization were induced by EMP1, and EMP37 but not by EMP13, EMP26 or FMRF. This ACE method provides a rapid tool for the detection of small peptides or drugs that bind to EBP.
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Affiliation(s)
- G W Caldwell
- The R.W. Johnson Pharmaceutical Research Institute, Spring House, PA, USA.
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22
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Heintz J, Hernandez M, Gomez FA. Use of a partial-filling technique in affinity capillary electrophoresis for determining binding constants of ligands to receptors. J Chromatogr A 1999; 840:261-8. [PMID: 10343401 DOI: 10.1016/s0021-9673(99)00278-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This work evaluates the concept of a partial-filling technique in affinity capillary electrophoresis (ACE) using two model systems: vancomycin from Streptomyces orientalis and carbonic anhydrase B (CAB, EC 4.2.1.1). In this technique the capillary is first partially-filled with ligand followed by a sample of receptor and non-interacting standard and electrophoresed. Analysis of the change in the mobility ratio, M, of the receptor, relative to the non-interacting standard, as a function of the concentration of the ligand, yields a value for the binding constant. These values agree well with those estimated using other binding and ACE techniques. Data demonstrating the quantitative potential of this method is presented.
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Affiliation(s)
- J Heintz
- Department of Chemistry and Biochemistry, California State University, Los Angeles 90032-8202, USA
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Heegaard NH, Nilsson S, Guzman NA. Affinity capillary electrophoresis: important application areas and some recent developments. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 715:29-54. [PMID: 9792496 DOI: 10.1016/s0378-4347(98)00258-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Affinity capillary electrophoresis (ACE) is a broad term referring to the separation by capillary electrophoresis of substances that participate in specific or non-specific affinity interactions during electrophoresis. The interacting molecules can be found free in solution or can be immobilized to a solid support. Every ACE mode has advantages and disadvantages. Each can be used for a wide variety of applications. This paper focuses on applications that include purification and concentration of analytes present in diluted solutions or complex matrices, quantitation of analytes based on calibration curves, and estimation of binding constants from direct and derived binding curves based on quantitation of analytes or on analyte migration shifts. A more recent chemicoaffinity strategy in capillary electrophoresis/capillary electrochromatography (CE/CEC) termed molecular imprinting ('plastic antibodies') is discussed as well. Although most ACE studies are aimed at characterizing small-molecular mass analytes such as drugs, hormones, and peptides, some efforts have been pursued to characterize larger biopolymers including proteins, such as immunoglobulins. Examples of affinity interactions that have been studied are antigen-antibody, hapten-antibody, lectin-sugar, drug-protein, and enzyme-substrate complexes using ultraviolet, laser-induced fluorescence, and mass spectrometer detectors. This paper also addresses the critical issue of background electrolyte selection and quantitation of analytes. Specific examples of bioaffinity applications are presented, and the future of ACE in the biomedical field is discussed.
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Affiliation(s)
- N H Heegaard
- Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark
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Tuffal G, Tuong A, Dhers C, Uzabiaga F, Rivière M, Picard C, Puzo G. Direct evidence of methylglucose lipopolysaccharides/palmitoyl-CoA noncovalent complexes by capillary zone electrophoresis-electrospray/mass spectrometry. Anal Chem 1998; 70:1853-8. [PMID: 9599585 DOI: 10.1021/ac971101r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mycobacterial methylglucose lipopolysaccharides (MGLPs) play an important regulatory role in the biosynthesis of long-chain fatty acids by forming complexes with neosynthesized acyl-CoA fatty acid derivatives. The MGLPs from Mycobacterium smegmatis were purified by high-performance anion-exchange chromatography and characterized by LSIMS and CE/ESI-MS. We investigated their interaction with palmitoyl-CoA using capillary zone electrophoresis with both direct and indirect UV detection. In the latter mode, the signal of the UV-transparent MGLPs decreased upon addition of increasing amounts of palmitoyl-CoA; while using direct UV detection, the addition of palmitoyl-CoA to the MGLPs revealed characteristic profiles. The major peak was assigned to the noncovalent MGLP/palmitoyl-CoA complex on the basis of its electrophoretic mobility. The abundance of the complex was found to increase until the MGLP/palmitoyl-CoA molar ratio reached a 1/1 stoichiometry. The existence of and the stoichiometry of this complex were assessed by CE/ESI mass spectrum analysis, showing pseudomolecular ions of the MGLP/palmitoyl-CoA complex. These results confirm that CE/ESI-MS is a powerful tool to characterize noncovalent molecular association.
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Affiliation(s)
- G Tuffal
- Institut de Pharmacologie et Biologie Structurale, CNRS, Toulouse, France
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Abstract
This review summarizes the advancement in operational modes and selected applications of the title technique over the past five years. Regarding operational modes particular emphasis is put upon increasing selectivity and resolution, hyphenation of capillary electrophoresis with techniques based on other than electromigration principles, the so-called chip technology and new ways of detection. In applications selected examples of chiral separation and separation of biopolymers (proteins, nucleic acids) are emphasized. It is demonstrated that capillary electrophoresis represents a complementary technique to high-performance column chromatography and in a number of cases it offers better separations than standard chromatographic procedures.
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Affiliation(s)
- Z Deyl
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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