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Azevedo AM, Nunes C, Moniz T, Pérez RL, Ayala CE, Rangel M, Reis S, Santos JL, Warner IM, Saraiva MLM. Studies of Protein Binding to Biomimetic Membranes Using a Group of Uniform Materials Based on Organic Salts Derived From 8-Anilino-1-naphthalenesulfonic Acid. APPLIED SPECTROSCOPY 2024; 78:806-814. [PMID: 38747750 PMCID: PMC11340245 DOI: 10.1177/00037028241249768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 03/27/2024] [Indexed: 08/22/2024]
Abstract
Tuning the 8-anilino-1-naphthalenesulfonic acid (ANS) structure usually requires harsh conditions and long reaction times, which can result in low yields. Herein, ANS was modified to form an ANS group of uniform materials based on organic salts (GUMBOS), prepared with simple metathesis reactions and distinct cations, namely tetrabutylammonium (N4444), tetrahexylammonium (N6666), and tetrabutylphosphonium (P4444). These ANS-based GUMBOS were investigated as fluorescent probes for membrane binding studies with four proteins having distinct physicochemical properties. Liposomes of 1,2-dimyristoyl-sn-glycero-3-phosphocholine were employed as membrane models as a result of their ability to mimic the structure and chemical composition of cell membranes. Changes in fluorescence intensity were used to monitor protein binding to liposomes, and adsorption data were fitted to a Freundlich-like isotherm. It was determined that [N4444][ANS] and [P4444][ANS] GUMBOS have enhanced optical properties and lipophilicity as compared to parent ANS. As a result, these two GUMBOS were selected for subsequent protein-membrane binding studies. Both [N4444][ANS] and [P4444][ANS] GUMBOS and parent ANS independently reached membrane saturation within the same concentration range. Furthermore, distinct fluorescence responses were observed upon the addition of proteins to each probe, which demonstrates the impact of properties such as lipophilicity on the binding process. The relative maintenance of binding cooperativity and maximum fluorescence intensity suggests that proteins compete with ANS-based probes for the same membrane binding sites. Finally, this GUMBOS-based approach is simple, rapid, and involves relatively small amounts of reagents, making it attractive for high-throughput purposes. These results presented herein can also provide relevant information for designing GUMBOS with ameliorated properties.
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Affiliation(s)
- Ana M.O. Azevedo
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Cláudia Nunes
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Tânia Moniz
- LAQV, REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
- LAQV, REQUIMTE, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Rocío L. Pérez
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia, USA
| | - Caitlan E. Ayala
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Maria Rangel
- LAQV, REQUIMTE, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Salette Reis
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - João L.M. Santos
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Isiah M. Warner
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA
| | - M. Lúcia M.F.S. Saraiva
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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Carabadjac I, Vormittag LC, Muszer T, Wuth J, Ulbrich MH, Heerklotz H. Transfer of ANS-Like Drugs from Micellar Drug Delivery Systems to Albumin Is Highly Favorable and Protected from Competition with Surfactant by "Reserved" Binding Sites. Mol Pharm 2024; 21:2198-2211. [PMID: 38625037 DOI: 10.1021/acs.molpharmaceut.3c00875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Micellar drug delivery systems (MDDS) for the intravenous administration of poorly soluble drugs have great advantages over alternative formulations in terms of the safety of their excipients, storage stability, and straightforward production. A classic example is mixed micelles of glycocholate (GC) and lecithin, both endogenous substances in human blood. What limits the use of MDDS is the complexity of the transitions after injection. In particular, as the MDDS disintegrate partially or completely after injection, the drug has to be transferred safely to endogenous carriers in the blood, such as human serum albumin (HSA). If this transfer is compromised, the drug might precipitate─a process that needs to be excluded under all circumstances. The key question of this paper is whether the high local concentration of GC at the moment and site of MDDS dissolution might transiently saturate HSA binding sites and, hence, endanger quick drug transfer. To address this question, we have used a new approach, which is time-resolved fluorescence spectroscopy of the single tryptophan in HSA, Trp-214, to characterize the competitive binding of GC and the drug substitute anilinonaphthalenesulfonate (ANS) to HSA. Time-resolved fluorescence of Trp-214 showed important advantages over established methods for tackling this problem. ANS has been the standard "model drug" to study albumin binding for decades, given its structural similarity to the class of naphthalene-containing acidic drugs and the fact that it is displaced from HSA by numerous drugs (which presumably bind to the same sites). Our complex global fit uses the critical approximation that the average lifetimes behave similarly to a single lifetime, but the resulting errors are found to be moderate and the results provide a convincing explanation of the, at first glance, counterintuitive behavior. Accordingly, and largely in line with the literature, we observed two types of sites binding ANS at HSA: 3 type A, rather peripheral, and 2 type B, likely more central sites. The latter quench Trp-214 by Förster Resonance Energy Transfer (FRET) with a rate constant of ≈0.4 ns-1 per ANS. Adding millimolar concentrations of GC displaces ANS from the A sites but not from B sites. At incomplete ANS saturation, this causes a GC-induced translocation of ANS from A to the more FRET-active B sites. This leads to the apparent paradox that the partial displacement of ANS from HSA increases its quenching effect on Trp-214. The most important conclusion is that (ANS-like) drugs cannot be displaced from the type-B sites, and consequently, drug transfer to these sites is not impaired by competitive binding of GC in the vicinity of a dissolving micelle. The second conclusion is that for unbound GC above the CMC (9 mM), ANS equilibrates between HSA and GC micelles but with a strong preference for free sites on HSA. That means that even persisting micelles would lose their cargo readily once exposed to HSA. For all MDDS sharing this property, targeted drug delivery approaches involving them as the nanocarrier would be pointless.
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Affiliation(s)
- Iulia Carabadjac
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Leonie C Vormittag
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Thomas Muszer
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Jakob Wuth
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Maximilian H Ulbrich
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstr. 17, 79104 Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Schan̈zlestr. 18, Freiburg 79104, Germany
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto M5s 3M2, Ontario, Canada
- BIOSS Centre for Biological Signalling Studies, Schan̈zlestr. 18, Freiburg 79104, Germany
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Trusova VM, Tarabara UK, Zhytniakivska OA, Vus KO, Gorbenko GP. Probing the interactions of novel europium coordination complexes with serum albumin. LUMINESCENCE 2021; 36:795-801. [PMID: 33398923 DOI: 10.1002/bio.4006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 12/29/2020] [Indexed: 11/09/2022]
Abstract
Molecular interactions between novel europium coordination complexes (EC) possessing superior cytotoxic activity and bovine serum albumin (BSA), the most prominent representative of plasma proteins, were assessed using fluorescence spectroscopy and molecular docking techniques. Cumulative results from fluorescent probe binding, fluorescence quenching and Förster resonance energy transfer studies revealed that the europium complexes V4 and V8 do not perturb the BSA structure, while V3, V5, and V7 induce partial unfolding of the polypeptide chain. Molecular docking studies coupled with analysis of the three-dimensional structure of the BSA-EC complexes showed that V4 and V8 reside in the vicinity of the protein IIA subdomain (Sudlow's site I), while V3, V5 and V5 were localized predominantly in the BSA IIIA subdomain (Sudlow's site II). Due to the intactness of the protein structure upon association with V4 and V8, these compounds may be recommended for further evaluation as potential antineoplastic agents.
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Affiliation(s)
- Valeriya M Trusova
- Department of Medical Physics and Biomedical Nanotechnologies, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, Ukraine
| | - Uliana K Tarabara
- Department of Medical Physics and Biomedical Nanotechnologies, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, Ukraine
| | - Olga A Zhytniakivska
- Department of Medical Physics and Biomedical Nanotechnologies, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, Ukraine
| | - Kateryna O Vus
- Department of Medical Physics and Biomedical Nanotechnologies, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, Ukraine
| | - Galyna P Gorbenko
- Department of Medical Physics and Biomedical Nanotechnologies, V.N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv, Ukraine
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Babinchak WM, Dumm BK, Venus S, Boyko S, Putnam AA, Jankowsky E, Surewicz WK. Small molecules as potent biphasic modulators of protein liquid-liquid phase separation. Nat Commun 2020; 11:5574. [PMID: 33149109 PMCID: PMC7643064 DOI: 10.1038/s41467-020-19211-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 09/28/2020] [Indexed: 12/14/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) of proteins that leads to formation of membrane-less organelles is critical to many biochemical processes in the cell. However, dysregulated LLPS can also facilitate aberrant phase transitions and lead to protein aggregation and disease. Accordingly, there is great interest in identifying small molecules that modulate LLPS. Here, we demonstrate that 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) and similar compounds are potent biphasic modulators of protein LLPS. Depending on context, bis-ANS can both induce LLPS de novo as well as prevent formation of homotypic liquid droplets. Our study also reveals the mechanisms by which bis-ANS and related compounds modulate LLPS and identify key chemical features of small molecules required for this activity. These findings may provide a foundation for the rational design of small molecule modulators of LLPS with therapeutic value.
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Affiliation(s)
- W Michael Babinchak
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Benjamin K Dumm
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science & Therapeutics, Case Western Reserve University, Cleveland, OH, USA
| | - Solomiia Boyko
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA
| | - Andrea A Putnam
- Center for RNA Science & Therapeutics, Case Western Reserve University, Cleveland, OH, USA
- Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Eckhard Jankowsky
- Center for RNA Science & Therapeutics, Case Western Reserve University, Cleveland, OH, USA
| | - Witold K Surewicz
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
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ANS Interacts with the Ca 2+-ATPase Nucleotide Binding Site. J Fluoresc 2020; 30:483-496. [PMID: 32146650 DOI: 10.1007/s10895-020-02518-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
Abstract
The binding of 8-anilino-1-naphthalene sulfonate (ANS) to the nucleotide binding domain (N-domain) of the sarcoplasmic reticulum Ca2+-ATPase (SERCA) was studied. Molecular docking predicted two ANS binding modes (BMI and BMII) in the nucleotide binding site. The molecular interaction was confirmed as the fluorescence intensity of ANS was dramatically increased when in the presence of an engineered recombinant N-domain. Molecular dynamics simulation showed BMI (which occupies the ATP binding site) as the mode that is stable in solution. The above was confirmed by the absence of ANS fluorescence in the presence of a fluorescein isothiocyanate (FITC)-labeled N-domain. Further, the labeling of the N-domain with FITC was hindered by the presence of ANS, i.e., ANS was bound to the ATP binding site. Importantly, ANS displayed a higher affinity than ATP. In addition, ANS binding led to quenching the N-domain intrinsic fluorescence displaying a FRET pattern, which suggested the existence of a Trp-ANS FRET couple. Nonetheless, the chemical modification of the sole Trp residue with N-bromosuccinimide (NBS) discarded the existence of FRET and instead indicated structural rearrangements in the nucleotide binding site during ANS binding. Finally, Ca2+-ATPase kinetics in the presence of ANS showed a partial mixed-type inhibition. The Dixon plot showed the ANS-Ca2+-ATPase complex as catalytically active, hence supporting the existence of a functional dimeric Ca2+-ATPase in sarcoplasmic reticulum vesicles. ANS may be used as a molecular platform for the development of more effective inhibitors of Ca2+-ATPase and appears to be a new fluorescent probe for the nucleotide binding site. Graphical Abstract Molecular docking of ANS to the nucleotide binding site of Ca2+-ATPase. ANS fluorescence increase reveals molecular interaction.
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Yokoi Y, Yao H. Organic nanoparticles of anion-based fluorophore 8-anilino-1-naphthalenesulfonate (ANS): Effects of ion-association and post-dilution. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Tayyab S, Min LH, Kabir MZ, Kandandapani S, Ridzwan NFW, Mohamad SB. Exploring the interaction mechanism of a dicarboxamide fungicide, iprodione with bovine serum albumin. CHEMICAL PAPERS 2019. [DOI: 10.1007/s11696-019-01015-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Foo YY, Kabir MZ, Periasamy V, Malek SNA, Tayyab S. Spectroscopic studies on the interaction of green synthesized-gold nanoparticles with human serum albumin. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Li J, Han Q, Wang X, Yu N, Yang L, Yang R, Wang C. Reduced aggregation and cytotoxicity of amyloid peptides by graphene oxide/gold nanocomposites prepared by pulsed laser ablation in water. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:4386-4394. [PMID: 25059878 DOI: 10.1002/smll.201401121] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/18/2014] [Indexed: 06/03/2023]
Abstract
A novel and convenient method to synthesize the nanocomposites combining graphene oxides (GO) with gold nanoparticles (AuNPs) is reported and their applications to modulate amyloid peptide aggregation are demonstrated. The nanocomposites produced by pulsed laser ablation (PLA) in water show good biocompatibility and solubility. The reduced aggregation of amyloid peptides by the nanocomposites is confirmed by Thioflavin T fluorescence and atomic force microscopy. The cell viability experiments reveals that the presence of the nanocomposites can significantly reduce the cytotoxicity of the amyloid peptides. Furthermore, the depolymerization of peptide fibrils and inhibition of their cellular cytotoxicity by GO/AuNPs is also observed. These observations suggest that the nanocomposites combining GO and AuNPs have a great potential for designing new therapeutic agents and are promising for future treatment of amyloid-related diseases.
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Affiliation(s)
- Jingying Li
- CAS Key Lab for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, (China)
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Chowdhury A, Choudhury A, Banerjee V, Banerjee R, Das KP. Spectroscopic studies of the unfolding of a multimeric protein α-crystallin. Biopolymers 2014; 101:549-60. [DOI: 10.1002/bip.22417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 08/19/2013] [Accepted: 09/23/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Aritra Chowdhury
- School of Chemistry; University of Manchester; Oxford Road, M13 9PL Manchester UK
- Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and Department of Biotechnology; Calcutta University; Ballygunge Circular Road Kolkata 700019 India
| | - Aparajita Choudhury
- Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and Department of Biotechnology; Calcutta University; Ballygunge Circular Road Kolkata 700019 India
| | - Victor Banerjee
- Department of Chemistry; Bose Institute; 93/1 A. P. C. Road Kolkata 700 009 India
| | - Rajat Banerjee
- Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and Department of Biotechnology; Calcutta University; Ballygunge Circular Road Kolkata 700019 India
| | - K. P. Das
- Department of Chemistry; Bose Institute; 93/1 A. P. C. Road Kolkata 700 009 India
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Orevi T, Lerner E, Rahamim G, Amir D, Haas E. Ensemble and single-molecule detected time-resolved FRET methods in studies of protein conformations and dynamics. Methods Mol Biol 2014; 1076:113-169. [PMID: 24108626 DOI: 10.1007/978-1-62703-649-8_7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most proteins are nanomachines that are selected to execute specific functions and therefore should have some degree of flexibility. The driving force that excites specific motions of domains and smaller chain elements is the thermal fluctuations of the solvent bath which are channeled to selected modes of motions by the structural constraints. Consequently characterization of the ensembles of conformers of proteins and their dynamics should be expressed in statistical terms, i.e., determination of probability distributions of the various conformers. This can be achieved by measurements of time-resolved dynamic non-radiative excitation energy transfer (trFRET) within ensembles of site specifically labeled protein molecules. Distributions of intramolecular segmental end-to-end distances and their fast fluctuations can be determined, and fast and slow conformational transitions within selected sections of the molecule can be monitored and analyzed. Both ensemble and single-molecule detection methods can be applied for data collection. In combination with synchronization methods, time-resolved FRET was also used for studies of fast conformational transitions, in particular the folding/unfolding transitions.
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Affiliation(s)
- Tomer Orevi
- The Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, Israel
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12
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Hassani L, Sajedi RH. Effect of artemin on structural transition of β-lactoglobulin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 105:24-28. [PMID: 23291197 DOI: 10.1016/j.saa.2012.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 10/24/2012] [Accepted: 12/02/2012] [Indexed: 06/01/2023]
Abstract
Encysted embryos of Artemia are exceptionally resistant to severe environmental stress. This resistance is thought to depend in part on the existence of a protein termed artemin. There is only little information about the function of artemin. It has been reported artemin is a thermostable protein with RNA-binding ability. In addition, it reduces the extent of aggregation significantly and enhances the efficiency of refolding and activity recovery of carbonic anhydrase and horseradish peroxidase. In this study, the effect of artemin purified from Artemia urmiana on bovine β-lactoglobulin (BLG) and its α-helical intermediate state has been evaluated by circular dichroism and intrinsic and extrinsic fluorescence spectroscopy. The results obtained in aqueous buffer show, artemin decreases the compactness of BLG structure and causes to the exposure of some hydrophobic groups. The results also indicate artemin has an inhibitory effect on β-sheet→α-helix transition in the secondary structure of β-lactoglobulin. Since this transition occurs during unfolding of β-lactoglobulin, it seems artemin influences on the folding pathway of β-lactoglobulin. This structural effect of artemin can result from its high surface hydrophobicity. Consequently, it is expected that artemin has chaperoning potency because of its effect on the folding of BLG.
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Affiliation(s)
- Leila Hassani
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45195-1159, Iran.
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The Anticancer Activity and HSA Binding Properties of the Structurally Related Platinum (II) Complexes. Appl Biochem Biotechnol 2012; 167:861-72. [DOI: 10.1007/s12010-012-9733-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 05/08/2012] [Indexed: 01/07/2023]
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14
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Evaluation of solute binding to proteins and intra-protein distances from steady state fluorescence measurements. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2012; 106:1-17. [DOI: 10.1016/j.jphotobiol.2011.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 11/01/2011] [Accepted: 11/07/2011] [Indexed: 12/28/2022]
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Ding F, Liu W, Diao JX, Sun Y. Characterization of Alizarin Red S binding sites and structural changes on human serum albumin: a biophysical study. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:352-359. [PMID: 21112139 DOI: 10.1016/j.jhazmat.2010.11.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 10/29/2010] [Accepted: 11/01/2010] [Indexed: 05/30/2023]
Abstract
Alizarin Red S (ARS), is a water-soluble, widely used anthraquinone dye synthesized by sulfonation of alizarin. In this report, the binding of ARS to human serum albumin (HSA) was characterized by employing fluorescence, UV/vis absorption, circular dichroism (CD), and molecular modeling methods. The data of fluorescence spectra displayed that the binding of ARS to HSA is the formation of HSA-ARS complex at 1:1 stoichiometric proportion. Hydrophobic probe 8-anilino-1-naphthalenesulfonic acid (ANS) was employed and elucidated that the dye was located in subdomain IIIA. This phenomenon corroborates the result of site-specific probe displacement experiments, which demonstrate the dye is at indole-benzodiazepine site (Sudlow's site II); and it is also consistent with guanidine hydrochloride (GuHCl) induced HSA unfolding studies and molecular modeling simulations. The features of the dye, which led to structural perturbations of HSA, have also been studied in detail by methods of UV/vis, CD and three-dimensional fluorescence spectroscopy.
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Affiliation(s)
- Fei Ding
- Department of Chemistry, China Agricultural University, Haidian District, Beijing, China
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