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Witos J, Samuelsson J, Cilpa-Karhu G, Metso J, Jauhiainen M, Riekkola ML. Partial filling affinity capillary electrophoresis including adsorption energy distribution calculations--towards reliable and feasible biomolecular interaction studies. Analyst 2015; 140:3175-82. [PMID: 25751597 DOI: 10.1039/c5an00210a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In this work, a method to study and analyze the interaction data in free solution by exploiting partial filling affinity capillary electrophoresis (PF-ACE) followed by adsorption energy distribution calculations (AED) prior model fit to adsorption isotherms will be demonstrated. PF-ACE-AED approach allowed the possibility to distinguish weak and strong interactions of the binding processes between the most common apolipoprotein E protein isoforms (apoE2, apoE3, apoE4) of high density lipoprotein (HDL) and apoE-containing HDL2 with major glycosaminoglycan (GAG) chain of proteoglycans (PGs), chondroitin-6-sulfate (C6S). The AED analysis clearly revealed the heterogeneity of the binding processes. The major difference was that they were heterogeneous with two different adsorption sites for apoE2 and apoE4 isoforms, whereas interestingly for apoE3 and apoE-containing HDL2, the binding was homogeneous (one site) adsorption process. Moreover, our results allowed the evaluation of differences in the binding process strengths giving the following order with C6S: apoE-containing HDL2 > apoE2 > apoE4 > apoE3. In addition, the affinity constant values determined could be compared with those obtained in our previous studies for the interactions between apoE isoforms and another important GAG chain of PGs - dermatan sulfate (DS). The success of the combination of AED calculations prior to non-linear adsorption isotherm model fit with PF-ACE when the concentration range was extended, confirmed the power of the system in the clarification of the heterogeneity of biological processes studied.
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Affiliation(s)
- Joanna Witos
- Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FIN-00014 University of Helsinki, Finland.
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Zhang X, Samuelsson J, Janson JC, Wang C, Su Z, Gu M, Fornstedt T. Investigation of the adsorption behavior of glycine peptides on 12% cross-linked agarose gel media. J Chromatogr A 2010; 1217:1916-25. [PMID: 20167326 DOI: 10.1016/j.chroma.2010.01.058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 12/02/2009] [Accepted: 01/18/2010] [Indexed: 11/15/2022]
Abstract
The highly cross-linked 12% agarose gel Superose 12 10/300 GL causes retardation of glycine peptides when mobile phases containing varying concentrations of acetonitrile in water are used. An investigation has been made into the retention mechanism behind this retardation using the glycine dipeptide (GG) and tripeptide (GGG) as models. The dependence of retention times of analytical-size peaks under different experimental conditions was interpreted such that the adsorption most probably was caused by the formation of hydrogen bonds but that electrostatic interactions cannot be ruled out. Thereafter, a nonlinear adsorption study was undertaken at different acetonitrile content in the eluent, using the elution by characteristic points (ECPs) method on strongly overloaded GG and GGG peaks. With a new evaluation tool, the adsorption energy distribution (AED) could be calculated prior to the model selection. These calculations revealed that when the acetonitrile content in the eluent was varied from 0% to 20% the interactions turned from (i) being homogenous (GG) or mildly heterogeneous (GGG), (ii) via a more or less stronger degree of heterogeneity around one site to (iii) finally a typical bimodal energy interaction comprising of two sites (GG at 20% and GGG at 10% and 20%). The Langmuir, Tóth and bi-Langmuir models described these interesting adsorption trends excellently. Thus, the retardation observed for these glycine peptides is interpreted as being of mixed-mode character composed of electrostatic bonds and hydrogen bonds.
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Affiliation(s)
- Xiaoou Zhang
- Department of Biological Science and Technology, School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian, 116024, China
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12
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Lämmerhofer M. Chiral recognition by enantioselective liquid chromatography: mechanisms and modern chiral stationary phases. J Chromatogr A 2009; 1217:814-56. [PMID: 19906381 DOI: 10.1016/j.chroma.2009.10.022] [Citation(s) in RCA: 514] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/30/2009] [Accepted: 10/07/2009] [Indexed: 11/19/2022]
Abstract
An overview of the state-of-the-art in LC enantiomer separation is presented. This tutorial review is mainly focused on mechanisms of chiral recognition and enantiomer distinction of popular chiral selectors and corresponding chiral stationary phases including discussions of thermodynamics, additivity principle of binding increments, site-selective thermodynamics, extrathermodynamic approaches, methods employed for the investigation of dominating intermolecular interactions and complex structures such as spectroscopic methods (IR, NMR), X-ray diffraction and computational methods. Modern chiral stationary phases are discussed with particular focus on those that are commercially available and broadly used. It is attempted to provide the reader with vivid images of molecular recognition mechanisms of selected chiral selector-selectand pairs on basis of solid-state X-ray crystal structures and simulated computer models, respectively. Such snapshot images illustrated in this communication unfortunately cannot account for the molecular dynamics of the real world, but are supposed to be helpful for the understanding. The exploding number of papers about applications of various chiral stationary phases in numerous fields of enantiomer separations is not covered systematically.
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Affiliation(s)
- Michael Lämmerhofer
- Christian Doppler Laboratory for Molecular Recognition Materials, Department of Analytical Chemistry and Food Chemistry, University of Vienna, Waehringer Strasse 38, A-1090 Vienna, Austria.
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Sandblad P, Arnell R, Samuelsson J, Fornstedt T. Approach for reliable evaluation of drug proteins interactions using surface plasmon resonance technology. Anal Chem 2009; 81:3551-9. [PMID: 19338267 DOI: 10.1021/ac900299p] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The surface plasmon resonance (SPR) biosensor was recently introduced to the analytical biochemical society for measuring small drug-protein interactions. However, the technique has many times been used without specifying the type of enantiomeric form of the chiral drug measured and/or with using a too narrow drug concentration range resulting in biased values of binding coefficients and sometimes even assumptions about single-site bindings although the binding in reality comprises a multisite interaction. In this study we will give guidelines for reliable experimental and methodological approaches to avoid these pitfalls. For this purpose, we also introduce a new tool, based on physical chemistry, to the sensor community; the calculation of the adsorption energy distribution (AED). The AED-calculations reveal the degree of heterogeneity directly from the SPR raw data and thus guide us into a narrower selection of probable models before the rival model fitting procedure. We demonstrate how to measure reliable equilibrium data for the two typically different cases: drug binding to (i) transport (plasma) proteins and to (ii) a target protein. Both the binding of the chiral beta-blocker propranolol to alpha(1)-acid glycoprotein (AGP) and that of the anticoagulant warfarin to human serum albumin were heterogeneous, with a few strong enantioselective sites and many weak nonselective sites. We also demonstrate how the multisite binding rapidly falsely turns to single-site as the concentration range is narrowed and how adding dimethyl sulfoxide to the buffer affects multisite drug-protein data. The binding of the enantiomers of the thrombin inhibitor melagatran was investigated on both thrombin and the transport proteins, revealing clear enantioselectivity for thrombin in favor of the active enantiomer, but almost similar binding properties for both enantiomers to the transport protein AGP. The AED-calculations verified that both these system has a unimodal energy distribution and are best described with a homogeneous adsorption model.
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Affiliation(s)
- Peter Sandblad
- Department of Physical and Analytical Chemistry, BMC Box 599, SE-751 24, Uppsala, Sweden
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Samuelsson J, Arnell R, Diesen JS, Tibbelin J, Paptchikhine A, Fornstedt T, Sjöberg PJR. Development of the Tracer-Pulse Method for Adsorption Studies of Analyte Mixtures in Liquid Chromatography Utilizing Mass Spectrometric Detection. Anal Chem 2008; 80:2105-12. [DOI: 10.1021/ac702399a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jörgen Samuelsson
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Robert Arnell
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Jarle S. Diesen
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Julius Tibbelin
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Alexander Paptchikhine
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Torgny Fornstedt
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
| | - Per J. R. Sjöberg
- Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 577, SE-751 23 Uppsala, Sweden, AstraZeneca Process R&D, SE-151 85, Södertälje, Sweden, Department of Biochemistry and Organic Chemistry, Uppsala University, BMC, Box 576, SE-751 23 Uppsala Sweden, and Department of Physical and Analytical Chemistry, Uppsala University, BMC, Box 599, SE-751 24 Uppsala, Sweden
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