1
|
Wolfbeis OS. Fluorescent chameleon labels for bioconjugation and imaging of proteins, nucleic acids, biogenic amines and surface amino groups. a review. Methods Appl Fluoresc 2021; 9. [PMID: 34340216 DOI: 10.1088/2050-6120/ac1a0a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/02/2021] [Indexed: 12/14/2022]
Abstract
Chameleon labels (ChLs) possess the unique property of changing (visible) color and fluorescence on binding to amino groups of biomolecules. MostChLs react with primary aliphatic amino groups such as those in lysine or with amino groups artificially introduced into polynucleic acids or saccharides, but someothers also react with secondary amino groups. Under controlled circumstances, the reactions are fairly specific. The review is subdivided into the following sections: (1) An introduction and classification of fluorescent labels; (2) pyrylium labels that undergo shortwave color changes upon labelling, typically from blue to red; (3) polymethine type of labels (that also undergo shortwave color changes, typically from green to blue; (4) various other (less common) chromogenic and fluorogenic systems; (5) hemicyanine labels that undergolongwavecolor changes, typically from yellow to purple; (6) the application of ChLs to labeling of proteins and oligonucleotides; (7) applications to fluorometric assays and sensing; (8) applications to fluorescence imaging of biomolecules; (9) applications in studies on affinity interactions (receptor-ligand binding); (10) applications in surface and interface chemistry; and (11) applications in chromatography, electrophoresis and isotachophoresis of biomolecules.
Collapse
Affiliation(s)
- Otto S Wolfbeis
- University of Regensburg, Institute of Analytical Chemistry, Chemo- and Biosensors, 94040 Regensburg, Germany
| |
Collapse
|
2
|
Guo X, Chen GH. Capillary electrophoresis-based methodology for screening of oligonucleotide aptamers. Biomed Chromatogr 2021; 35:e5109. [PMID: 33660332 DOI: 10.1002/bmc.5109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 01/28/2023]
Abstract
As a new molecular recognition element, oligonucleotide aptamer not only has higher affinity and specificity to target molecules, but also has the advantages of wide recognition range, in vitro synthesis and chemical stability compared with conventional antibodies. Since a kind of screening method termed systematic evolution of ligands by exponential enrichment (SELEX) was reported, scientists have extensively researched the methodology of how to highly and efficiently screen out aptamers from a library consisting of a large number of random oligonucleotides. Certainly capillary electrophoresis-based screening methodologies, including nonequilibrium capillary electrophoresis of equilibrium mixtures, equilibrium capillary electrophoresis of equilibrium mixtures, non-SELEX, ideal-filter capillary electrophoresis, capillary transient isotachophoresis, etc., are revolutionary. Compared with conventional SELEX, these capillary electrophoresis-based methodologies show incomparable advantages such as the single-round screening of aptamers and increased successful screening rate. Methodology studies on the screening process of aptamers are comprehensively reviewed.
Collapse
Affiliation(s)
- Xin Guo
- College of Food and Bioengineering, Jiangsu University, Zhenjiang, China.,Periodicals Agency of Jiangsu University, Zhenjiang, China
| | - Guan-Hua Chen
- College of Food and Bioengineering, Jiangsu University, Zhenjiang, China
| |
Collapse
|
3
|
Zhu C, Yang G, Ghulam M, Li L, Qu F. Evolution of multi-functional capillary electrophoresis for high-efficiency selection of aptamers. Biotechnol Adv 2019; 37:107432. [PMID: 31437572 DOI: 10.1016/j.biotechadv.2019.107432] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/24/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023]
Abstract
Aptamers have drawn considerable attention as newly emerging molecular recognition elements in clinical diagnostics, drug delivery, therapeutics, environmental monitoring, and food safety analyses. As the in vitro screening antibody analogs, aptamers are enabled to recognize various types of targets with high affinity and specificity like or even superior to antibodies. However, the restrictions and inefficiency of selection have been hampering their wider application. Among various modified systematic evolution of ligands by exponential enrichment (SELEX) methods, capillary electrophoresis (CE)-SELEX holds multiple functions and advantages with the powerful qualitative and quantitative analysis capabilities, less consumption of sample and analytical reagent, natural binding environment, higher screening efficiency, and availability in multiple modes. This review summarizes the key developments in the area of CE-SELEX by leading research groups, including our teams' ten years of research and experience to help researchers fully understand and utilize CE-SELEX. Aptamers' history, applications, as well as the SELEX developments, have been briefly described; the advantages of CE-SELEX are highlighted compared with the conventional SELEX methods. Further, we describe some essential CE-SELEX models and provide an overview of the CE-SELEX, including the targets and ssDNA library, every technical point in the selection process, and post-SELEX protocol. We expect this review will inspire more researchers to have insight into the screening problems from CE-SELEX viewpoint and will help to improve the selection efficiency and probability of success to meet the growing needs of aptamers' discovery in bioanalytical and medical fields.
Collapse
Affiliation(s)
- Chao Zhu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Ge Yang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Murtaza Ghulam
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Linsen Li
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China
| | - Feng Qu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing 100081, China.
| |
Collapse
|
4
|
Online reaction based single-step capillary electrophoresis-systematic evolution of ligands by exponential enrichment for ssDNA aptamers selection. Anal Chim Acta 2019; 1070:112-122. [PMID: 31103164 DOI: 10.1016/j.aca.2019.04.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/19/2019] [Accepted: 04/15/2019] [Indexed: 12/29/2022]
Abstract
Capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX) has proven to be an effective technique for aptamers selection. In this study, we present an online reaction based convenient single-step CE-SELEX (ssCE-SELEX) mode with human thrombin (H-Thr) as a model target. The selection progress was monitored through bulk Kd analysis, which showed more than a 1000-fold improvement over the initial library after two rounds of selection. Three selected candidate sequences presented high binding affinities against H-Thr with nanomolar (nM) Kd determined by nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM, 56.4-177.1 nM) and CE based non-linear fitting (CE-NLF, 98.2-199.7 nM). They also exhibited high specificities towards H-Thr compared with bovine thrombin, IgG, lysozyme, and lactoferrin. Meanwhile, the Kd results by isothermal titration calorimetry (ITC) confirmed the effective CE in measuring the aptamer affinity. In addition, three candidates were applied as aptasensors in the AuNPs based colorimetric assay, which showed visible color change and good linear relationships (R2 > 0.93) with H-Thr concentration. Furthermore, molecular dynamics (MD) simulation was performed to validate the binding of the three candidates with H-Thr by binding sites and binding free energy. The ssCE-SELEX method avoids off-line incubation, saves time and sample, and may provide a universal and convenient method for aptamers selection.
Collapse
|
5
|
Zhu C, Wang X, Li L, Hao C, Hu Y, Rizvi AS, Qu F. Online reaction based single-step CE for Protein-ssDNA complex obtainment to assist aptamer selection. Biochem Biophys Res Commun 2018; 506:169-175. [PMID: 30340834 DOI: 10.1016/j.bbrc.2018.08.189] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 01/07/2023]
Abstract
CE application in aptamer selection (CE-SELEX) shows more advantages than other selection methods. In this study, an online reaction based single-step CE (ssCE) mode was employed for fast obtaining protein-ssDNA complex. Using human thrombin (H-Thr) and its aptamer Apt29 as models, we accomplished the procedures of mixing, reaction, separation, detection and complex collection in single step online process, which took about 10 min to obtain the H-Thr/Apt29 complex. Important factors, affecting the aptamer and H-Thr interaction (buffer, ratio of aptamer and H-Thr amount), and complex separation and collection (voltage and temperature) were discussed. Later, the online reaction of H-Thr with an 80 nt ssDNA library was realized under optimized conditions, and the H-Thr/ssDNA complex was collected and subjected to PCR. By analyzing the PCR product through capillary gel electrophoresis, the resulting approximative 80 nt DNA length validated the ssDNA sequence in complex. To confirm the availability of ssCE mode, two ssDNA libraries with different lengths (56 nt and 82 nt ssDNA) and three proteins (platelet derived growth factor, PDGF-BB; lactoferrin protein, LF; and single-strand DNA binding protein, SSB) were utilized. Their complex peaks were also observed in electropherograms as expected. Additionally, the online incubation of ssDNA and H-Thr was achieved by stopping the separation voltage for some time when ssDNA passed the H-Thr zone. Our results show the ssCE mode has apparent merits of saving time and sample cost for aptamer selection against protein targets.
Collapse
Affiliation(s)
- Chao Zhu
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Xiaoqian Wang
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Linsen Li
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Chenxu Hao
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Youhao Hu
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Aysha Sarfraz Rizvi
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China
| | - Feng Qu
- The School of Life Science, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China.
| |
Collapse
|
6
|
Beloborodov SS, Panferov VG, Safenkova IV, Krylova SM, Dzantiev BB, Krylov SN. Unexpected Electrophoretic Behavior of Complexes between Rod-like Virions and Bivalent Antibodies. Anal Chem 2016; 88:11908-11912. [PMID: 27934118 DOI: 10.1021/acs.analchem.6b03779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Here we report on the unexpected electrophoretic behavior of complexes between rod-like virus particles (virions) and bivalent antibodies. The multiple complexes formed by the virions and antibodies migrated with electrophoretic mobilities of much greater absolute values than those of the unbound virions or antibodies while typically complexes have mobilities intermediate to those of their components. We hypothesized that the mobilities of unusually high absolute values are caused by the cross-linking of virions by bivalent antibodies into aggregates with prominent side-to-side binding. Theoretically, the mobility of such aggregates should be proportional to the square root of the number of cross-linked virions. The formation of virion aggregates with prominent side-to-side binding was confirmed by atomic force microscopy. The dependence of the aggregate mobility on the number of cross-linked virions can be used to estimate this number.
Collapse
Affiliation(s)
- Stanislav S Beloborodov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
| | - Vasily G Panferov
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences , Moscow 119071, Russia
| | - Irina V Safenkova
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences , Moscow 119071, Russia
| | - Svetlana M Krylova
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
| | - Boris B Dzantiev
- A.N. Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences , Moscow 119071, Russia
| | - Sergey N Krylov
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
| |
Collapse
|
7
|
Lin X, Sun X, Luo S, Liu B, Yang C. Development of DNA-based signal amplification and microfluidic technology for protein assay: A review. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.02.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
8
|
Bao J, Krylova SM, Cherney LT, Hale RL, Belyanskaya SL, Chiu CH, Shaginian A, Arico-Muendel CC, Krylov SN. Predicting Electrophoretic Mobility of Protein–Ligand Complexes for Ligands from DNA-Encoded Libraries of Small Molecules. Anal Chem 2016; 88:5498-506. [DOI: 10.1021/acs.analchem.6b00980] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Jiayin Bao
- Department
of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Svetlana M. Krylova
- Department
of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Leonid T. Cherney
- Department
of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | - Robert L. Hale
- GlaxoSmithKline, 830 Winter Street, Waltham, Massachusetts 02451-8714, United States
| | | | - Cynthia H. Chiu
- GlaxoSmithKline, 830 Winter Street, Waltham, Massachusetts 02451-8714, United States
| | - Alex Shaginian
- GlaxoSmithKline, 830 Winter Street, Waltham, Massachusetts 02451-8714, United States
| | | | - Sergey N. Krylov
- Department
of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| |
Collapse
|
9
|
Sensitive analysis of α-synuclein by nonlinear laser wave mixing coupled with capillary electrophoresis. Anal Biochem 2016; 500:51-9. [PMID: 26874019 DOI: 10.1016/j.ab.2016.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 12/31/2015] [Accepted: 01/13/2016] [Indexed: 01/07/2023]
Abstract
Multi-photon nonlinear laser wave-mixing spectroscopy is a novel absorption-based technique that offers excellent detection sensitivity for biomedical applications, including early diagnosis and investigation of neurodegenerative diseases. α-Synuclein is linked to Parkinson's disease (PD), and characterization of its oligomers and quantification of the protein may contribute to understanding PD. The laser wave-mixing signal has a quadratic dependence on analyte concentration, and hence the technique is effective in monitoring small changes in concentration within biofluids. A wide variety of labels can be employed for laser wave-mixing detection due to its ability to detect both chromophores and fluorophores. In this investigation, two fluorophores and a chromophore are studied and used as labels for the detection of α-synuclein. Wave-mixing detection limits of PD-related protein conjugated with fluorescein isothiocyanate, QSY 35 acetic acid, succinimidyl ester, and Chromeo P503 were determined to be 1.4 × 10(-13) M, 1.4 × 10(-10) M, and 1.9 × 10(-13) M, respectively. Based on the laser probe volume used, the corresponding mass detection limits were determined to be 1.1 × 10(-23) mol, 1.1 × 10(-20) mol, and 1.5 × 10(-23) mol. This study also presents molecular-based separation and quantification of α-synuclein by laser wave mixing coupled with capillary electrophoresis.
Collapse
|
10
|
Lin X, Chen Q, Liu W, Yi L, Li H, Wang Z, Lin JM. Assay of multiplex proteins from cell metabolism based on tunable aptamer and microchip electrophoresis. Biosens Bioelectron 2014; 63:105-111. [PMID: 25063921 DOI: 10.1016/j.bios.2014.07.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/29/2014] [Accepted: 07/05/2014] [Indexed: 12/24/2022]
Abstract
A simple and rapid method for multiplex protein assay based on tunable aptamer by microchip electrophoresis has been developed. Different lengths of aptamers can modulate the electrophoretic mobility of proteins, allowing the protein molecules to be effectively separated in hydroxyethyl cellulose buffer with 1.00 mM magnesium ion. A non-specific DNA was exploited as an internal standard to achieve the quantitative assay and to reduce the interference. A fluorescence dye SYBR gold was exploited to improve the sensitivity and to suppress the interference from sample matrix. Under optimum conditions, quantitative assay of PDGF-BB (R(2)=0.9986), VEGF165 (R(2)=0.9909), and thrombin (R(2)=0.9947) were achieved with a dynamic range in the 5.00-150.0 nM and RSDs in the 5.87-16.3% range. The recoveries were varied from 83.6% to 113.1%. Finally, the proposed method was successfully applied to analyze cell secretions, and then the concentration of PDGF-BB and VEGF165 were detected from 5.15 nM to 2.03 nM, and 3.14 to 2.53 nM, respectively, indicating the established method can be used to analyze cell secretions.
Collapse
Affiliation(s)
- Xuexia Lin
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Qiushui Chen
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Wu Liu
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Linglu Yi
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Haifang Li
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Zhihua Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jin-Ming Lin
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
11
|
Carcino-embryonic antigen detection based on fluorescence resonance energy transfer between quantum dots and graphene oxide. Biosens Bioelectron 2014; 59:397-403. [PMID: 24768819 DOI: 10.1016/j.bios.2014.04.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 03/20/2014] [Accepted: 04/01/2014] [Indexed: 01/01/2023]
Abstract
The mixture of graphene oxide (GO) and aptamer labeled fluorophore is widely used in developing fluorescent sensors for the analysis of biomolecules, according to the light signal 'off-on' procedure. Moreover, the laser-induced fluorescence-coupled affinity probe capillary electrophoresis (APCE) technique has been broadly applied for the separation of micromolecules. Here, a strategy is proposed for analysis of content of carcino-embryonic antigen (CEA) based on the combination of GO and quantum dots labeling aptamer (QD-aptamer) by capillary electrophoresis (CE). The method has three advantages: (i) combined with CE, only few samples are required and efficiency of separation is high, (ii) fluorescent detection can be carried out after separation of GO and fluorescence probe combined with targets by CE, while fluorescence detection sensitivity had been greatly improved, and (iii) the issues of APCE, including the effect of excess fluorescence probe and maximizing separation between analytes, could be solved by introducing GO. It has been proved that QD-aptamer-CEA complex can completely dissociate from GO. Results show that the fluorescence intensity has a linear relationship with the concentration of CEA in the range from 0.257 to 12.9 ng/mL, and the limit of detection is approximately 5 pg/mL (S/N=3). The proposed method with high specificity has been applied for the accurate analysis of content of CEA in patient׳s serum.
Collapse
|
12
|
Liyanage R, Krylova SM, Krylov SN. Minimizing adsorption of histidine-tagged proteins for the study of protein–deoxyribonucleic acid interactions by kinetic capillary electrophoresis. J Chromatogr A 2013; 1322:90-6. [DOI: 10.1016/j.chroma.2013.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/31/2013] [Accepted: 11/01/2013] [Indexed: 01/24/2023]
|
13
|
de Jong S, Epelbaum N, Liyanage R, Krylov SN. A semipermanent coating for preventing protein adsorption at physiological pH in kinetic capillary electrophoresis. Electrophoresis 2012; 33:2584-90. [DOI: 10.1002/elps.201200153] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
14
|
Johannesen SA, Beeren SR, Blank D, Yang BY, Geyer R, Hindsgaul O. Glycan analysis via derivatization with a fluorogenic pyrylium dye. Carbohydr Res 2012; 352:94-100. [DOI: 10.1016/j.carres.2012.02.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
|
15
|
de Jong S, Krylov SN. Pressure-based approach for the analysis of protein adsorption in capillary electrophoresis. Anal Chem 2011; 84:453-8. [PMID: 22107082 DOI: 10.1021/ac2030333] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein adsorption to inner capillary walls creates a major obstacle in all applications of capillary electrophoresis involving protein samples. The problem is especially severe in kinetic capillary electrophoresis (KCE) techniques, which are used to study protein-ligand interactions at physiological conditions and, thus, cannot utilize extreme pH. A variety of coatings exist to reduce protein adsorption in CE, each expressing a unique surface chemistry that interacts with individual proteins differently. Here we introduce a simple pressure-based method for the qualitative assessment of protein adsorption that can facilitate the direct antiadhesive ranking of several coatings toward a protein of interest. In this approach, a short plug of the protein is injected into a capillary and propagated through with a pressure low enough to ensure adequate Taylor dispersion. The experiment is performed with a nonmodified commercial instrument in a pseudo-two-detector approach. The two detectors are mimicked by using two different distances from the capillary inlet to a single detector. If the peak area and shape do not change with changing distance, the protein does not adsorb appreciably, while a decreasing peak area with increasing distance infers inner surface adsorption. The magnitude change of the peak area between the two distances along with the overall peak shape is used to gauge the extent of protein adsorption. By using this method, we ranked antiadhesive properties of different wall chemistries for a series of proteins. The described method will be useful for optimizing protein analysis by CE and, in particular, for KCE experiments that investigate how proteins interact with their respective ligands.
Collapse
Affiliation(s)
- Stephanie de Jong
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | | |
Collapse
|
16
|
Bao J, Krylova SM, Wilson DJ, Reinstein O, Johnson PE, Krylov SN. Kinetic Capillary Electrophoresis with Mass-Spectrometry Detection (KCE-MS) Facilitates Label-Free Solution-Based Kinetic Analysis of Protein-Small Molecule Binding. Chembiochem 2011; 12:2551-4. [DOI: 10.1002/cbic.201100617] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Indexed: 01/22/2023]
|
17
|
Krylova SM, Dove PM, Kanoatov M, Krylov SN. Slow-dissociation and slow-recombination assumptions in nonequilibrium capillary electrophoresis of equilibrium mixtures. Anal Chem 2011; 83:7582-5. [PMID: 21853979 DOI: 10.1021/ac2018876] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) is a kinetic affinity method with both analytical and preparative applications. NECEEM requires that the dissociation of the complexes be negligible in its first phase and the recombination of the dissociated complexes be negligible in its second phase. Here, we introduce a method, which facilitates easy examination of whether or not these requirements are satisfied. We derived expressions for two parameters, termed the slow-dissociation parameter (SDP) and slow-recombination parameter (SRP), which can be used to assess the assumptions. Both parameters should be much less than 1 for the assumptions to be satisfied. We calculated the two parameters for new and previously published NECEEM experiments and found that the assumptions were satisfied in all of them. Finally, we discuss changes to NECEEM conditions that should be done if the assumptions are found not to be satisfied. The SDP/SRP assessment helps to easily validate the results of NECEEM-based analyses and thus makes the NECEEM method more robust.
Collapse
Affiliation(s)
- Svetlana M Krylova
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, Ontario M3J 1P3, Canada
| | | | | | | |
Collapse
|