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Singh PK, Kotia V, Ghosh D, Mohite GM, Kumar A, Maji SK. Curcumin modulates α-synuclein aggregation and toxicity. ACS Chem Neurosci 2013; 4:393-407. [PMID: 23509976 DOI: 10.1021/cn3001203] [Citation(s) in RCA: 208] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In human beings, Parkinson's disease (PD) is associated with the oligomerization and amyloid formation of α-synuclein (α-Syn). The polyphenolic Asian food ingredient curcumin has proven to be effective against a wide range of human diseases including cancers and neurological disorders. While curcumin has been shown to significantly reduce cell toxicity of α-Syn aggregates, its mechanism of action remains unexplored. Here, using a series of biophysical techniques, we demonstrate that curcumin reduces toxicity by binding to preformed oligomers and fibrils and altering their hydrophobic surface exposure. Further, our fluorescence and two-dimensional nuclear magnetic resonance (2D-NMR) data indicate that curcumin does not bind to monomeric α-Syn but binds specifically to oligomeric intermediates. The degree of curcumin binding correlates with the extent of α-Syn oligomerization, suggesting that the ordered structure of protein is required for effective curcumin binding. The acceleration of aggregation by curcumin may decrease the population of toxic oligomeric intermediates of α-Syn. Collectively; our results suggest that curcumin and related polyphenolic compounds can be pursued as candidate drug targets for treatment of PD and other neurological diseases.
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Affiliation(s)
- Pradeep K. Singh
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
| | - Vasudha Kotia
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
| | - Dhiman Ghosh
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
| | - Ganesh M. Mohite
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
| | - Samir K. Maji
- Department of Biosciences and Bioengineering and ‡Wadhwani Research
Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra,
India 400076
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Aboel Dahab A, El-Hag D. Rapid analysis of NSAIDs binding to β-cyclodextrin using the simultaneous measurement of absorption and circular dichroism with a novel multi-cell low-volume device. Anal Bioanal Chem 2012; 404:1839-50. [DOI: 10.1007/s00216-012-6286-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/02/2012] [Accepted: 07/18/2012] [Indexed: 11/30/2022]
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Mislovičová D, Katrlík J, Paulovičová E, Gemeiner P, Tkac J. Comparison of three distinct ELLA protocols for determination of apparent affinity constants between Con A and glycoproteins. Colloids Surf B Biointerfaces 2012; 94:163-9. [DOI: 10.1016/j.colsurfb.2012.01.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/22/2011] [Accepted: 01/23/2012] [Indexed: 11/28/2022]
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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]
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Mekmene O, Gaucheron F. Determination of calcium-binding constants of caseins, phosphoserine, citrate and pyrophosphate: A modelling approach using free calcium measurement. Food Chem 2011; 127:676-82. [PMID: 23140718 DOI: 10.1016/j.foodchem.2010.12.121] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 12/22/2010] [Accepted: 12/28/2010] [Indexed: 11/30/2022]
Abstract
Dairy products contain large amount of calcium which is bound to caseins and different chelating agents like citrate and polyphosphates. The present study aimed to determine the calcium-binding capacities of phosphoserine (SerP), caseinophosphopeptide (CPP), β-casein, caseinate, citrate and pyrophosphate in the same conditions of temperature, pH and ionic strength. The free calcium (Ca(2+)) was measured using a calcium ion-selective electrode and plotted as a function of total calcium concentration. The association constants and the number of calcium-binding sites were determined by fitting the experimental data to a theoretical model. The phosphate groups of caseins were the main binding sites with evidence for participation of carboxylate groups. The intrinsic association constants determined by the best fit of the data were in the order: pyrophosphate (557×10(3)M(-1))>citrate (20×10(3)M(-1))>β-casein (5×10(3)M(-1))>caseinate, CPP and SerP (∼10(3)M(-1)). These findings may be of interest for the development of calcium-enriched products to overcome calcium deficiency in specific populations.
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Affiliation(s)
- Omar Mekmene
- INRA/AGROCAMPUS OUEST, UMR1253 Science et Technologie du Lait et de l'Œuf, 65 rue de Saint Brieuc, F-35042 Rennes Cedex, France
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Sayago A, Asuero AG. Spectrophotometric evaluation of stability constants of 1:1 weak complexes from continuous variation data. Int J Pharm 2006; 321:94-100. [PMID: 16824712 DOI: 10.1016/j.ijpharm.2006.05.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 05/02/2006] [Accepted: 05/05/2006] [Indexed: 11/16/2022]
Abstract
A bilogarithmic hyperbolic cosine method for the spectrophotometric evaluation of stability constants of 1:1 weak complexes from continuous variation data has been devised and applied to literature data. A weighting scheme, however, is necessary in order to take into account the transformation for linearization. The method may be considered a useful alternative to methods in which one variable is involved on both sides of the basic equation (i.e. Heller and Schwarzenbach, Likussar and Adsul and Ramanathan). Classical least squares lead in those instances to biased and approximate stability constants and limiting absorbance values. The advantages of the proposed method are: the method gives a clear indication of the existence of only one complex in solution, it is flexible enough to allow for weighting of measurements and the computation procedure yield the best value of logbeta11 and its limit of error. The agreement between the values obtained by applying the weighted hyperbolic cosine method and the non-linear regression (NLR) method is good, being in both cases the mean quadratic error at a minimum.
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Affiliation(s)
- Ana Sayago
- Department of Analytical Chemistry, Faculty of Pharmacy, The University of Seville, 41012 Seville, Spain
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Boccio M, Sayago A, Asuero AG. A bilogarithmic method for the spectrophotometric evaluation of stability constants of 1:1 weak complexes from mole ratio data. Int J Pharm 2006; 318:70-7. [PMID: 16647826 DOI: 10.1016/j.ijpharm.2006.03.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Accepted: 03/17/2006] [Indexed: 10/24/2022]
Abstract
The absorbance changes that occur when the mole ratio of the components of ligand complex equilibria is varied while the concentration of one component is kept constant (mole ratio method) allow evaluating stability constants in favourable conditions. Values of the corresponding stability (association) constants are normally assigned on the basis of spectrophotometric analysis. Determination of stability constants can be performed by a number of linear procedures, but most of these, suffer from theoretical and practical drawbacks, e.g., linear transformation of the rectangular hyperbola type of binding constants, is valid only when one of the two species is present in a large excess. A rigorous treatment of the experimental mole ratio data for 1:1 weak complexes is carried out in this paper with the aim of eliminating some of the assumptions involved in the other methods usually applied for evaluating stability constants. Orthogonal regression is required in order to take into account the error in both axes. The method has been applied to literature data for the iron(III)-thiocyanate and nickel(II)-selenocyanate systems, as well as to a number of host-guest cyclodextrin complexes.
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Affiliation(s)
- Maravillas Boccio
- Department of Analytical Chemistry, Faculty of Pharmacy, The University of Seville, 41012 Seville, Spain
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Veldhuis G, Vos EPP, Broos J, Poolman B, Scheek RM. Evaluation of the flow-dialysis technique for analysis of protein-ligand interactions: an experimental and a monte carlo study. Biophys J 2004; 86:1959-68. [PMID: 15041640 PMCID: PMC1304051 DOI: 10.1016/s0006-3495(04)74259-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Flow dialysis has found widespread use in determining the dissociation constant (KD) of a protein-ligand interaction or the amount of available binding sites (E0). This method has the potency to measure both these parameters in a single experiment and in this article a method to measure simultaneously the KD and E0 is presented, together with an extensive error analysis of the method. The flow-dialysis technique is experimentally simple to perform. However, a number of practical aspects of this method can have a large impact on the outcome of KD and E0. We have investigated all sources of significant systematic and random errors, using the interaction between mannitol and its transporter from Escherichia coli as a model. Monte Carlo simulations were found to be an excellent tool to assess the impact of these errors on the binding parameters and to define the experimental conditions that allow their most accurate estimation.
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Affiliation(s)
- Gertjan Veldhuis
- Department of Biochemistry and Biophysical Chemistry, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
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Comparison of domains function between cellobiohydrolase I and endoglucanase I from Trichoderma pseudokoningii S-38 by limited proteolysis. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1177(03)00070-5] [Citation(s) in RCA: 10] [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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Orosz F, Ovádi J. A simple method for the determination of dissociation constants by displacement ELISA. J Immunol Methods 2002; 270:155-62. [PMID: 12379321 DOI: 10.1016/s0022-1759(02)00295-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previously, we have described a linearization procedure for the determination of dissociation constants of antigen-antibody interactions using data from enzyme-linked immunosorbent assays (ELISA) [J. Immunol. Methods 143 (1991) 119]. Here, we present a new linearization procedure-based partly on the former one-to evaluate quantitatively the data of displacement ELISAs. It renders possible the determination of dissociation constants of complexes formed between immobilised antigens and the displacing molecules without knowing the explicit concentration of the antigen and the dissociation constant and stoichiometry of the immunocomplex. In addition, determination of the concentration of specific antibody in the serum is not necessary since the equations use only the ratio of serum concentration and apparent dissociation constant of the immunocomplex (both of which can be expressed as serum dilutions). The method has been applied to determine the strength of immobilised hexokinase-tubulin interactions (K(d)=1.2 microM) from a displacement ELISA using antihexokinase serum. The applicability and limitations of the procedure are discussed on the basis of both the experimental and theoretical data.
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Affiliation(s)
- Ferenc Orosz
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, POB 7, H-1518, Hungary.
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Fuchs H, Gessner R. Iodination significantly influences the binding of human transferrin to the transferrin receptor. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1570:19-26. [PMID: 11960684 DOI: 10.1016/s0304-4165(02)00146-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The human transferrin receptor (TfR) and its ligand, the serum iron carrier transferrin, serve as a model system for endocytic receptors. Although the complete structure of the receptor's ectodomain and a partial structure of the ligand have been published, conflicting results still exist about the magnitude of equilibrium binding constants, possibly due to different labeling techniques. In the present study, we determined the equilibrium binding constant of purified human TfR and transferrin. The results were compared to those obtained with either iodinated TfR or transferrin. Using an enzyme-linked assay for receptor-ligand interactions based on the published direct calibration ELISA technique, we determined an equilibrium constant of Kd=0.22 nM for the binding of unmodified human Tf to surface-immobilized human TfR. In a reciprocal experiment using soluble receptor and surface-bound transferrin, a similar constant of Kd=0.23 nM was measured. In contrast, covalent labeling of either TfR or transferrin with 125I reduced the affinity 3-5-fold to Kd=0.66 nM and Kd=1.01 nM, respectively. The decrease in affinity upon iodination of transferrin is contrasted by an only 1.9-fold decrease in the association rate constant, suggesting that the iodination affects rather the dissociation than the association kinetics. These results indicate that precautions should be taken when interpreting equilibrium and rate constants determined with covalently labeled components.
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Affiliation(s)
- Hendrik Fuchs
- Institut für Laboratoriumsmedizin und Pathobiochemie, Medizinische Fakultät Charité der Humboldt-Universität zu Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, D-13353, Berlin, Germany
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