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Mashrai A, Manea YK, Mahmood A. Insight into the interaction of 5,6 epoxy-cholesterols with human serum albumin. Arch Biochem Biophys 2024; 756:109993. [PMID: 38636691 DOI: 10.1016/j.abb.2024.109993] [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] [Received: 12/31/2023] [Revised: 03/15/2024] [Accepted: 04/12/2024] [Indexed: 04/20/2024]
Abstract
5,6-Epoxy-cholesterols has been recently revealed to control metabolic pathway in breast cancer, which makes investigating their binding interaction with human serum albumin (HSA) an attractive field of research. The main aim of this article is to examine the binding interaction of 5,6 α-epoxy-cholesterol (5,6 α EC) and 5,6 β-epoxy-cholesterol (5,6 β- EC) with HSA using different spectroscopic methods and molecular modeling. These compounds interact with HSA via hydrophobic interactions and hydrogen bonds with binding constants 6.3 × 105 M-1 for 5,6 α-epoxy-cholesterol and 6.9 × 105 M-1 for 5,6 β-epoxy-cholesterol besides, the mechanism of the interaction can be attributed to static quenching. Circular dichroism data indicated that the α-helical content of HSA increased from 50.5 to 59.8 and 61.1 % after the addition of 5,6 α-ECs and 5,6 β-EC, respectively, with a ratio of 1:2. Thermodynamic analysis revealed that binding between 5,6-epoxy-cholesterols and HSA is spontaneous and entropy-driven. The molecular docking and esterase-like activity experiments were performed to envision a link between the experimental and theoretical results. The optimal binding site of 5,6-epoxy-cholesterols with HSA was located in subdomain IIA. Moreover, theoretical calculations were performed using the B3LYP function with the 6-311++G (d,p) basis set, indicating the HOMO-LUMO energy gap of 7.874 eV for 5,6 α-epoxy-cholesterol and 7.873 eV for 5,6 β-epoxy-cholesterol. The obtained findings are assumed to provide basic data for understanding the binding interactions of HSA with oxysterol compounds, which could help explore the pharmacokinetics and pharmacodynamics of oxysterol compounds.
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Affiliation(s)
- Ashraf Mashrai
- Department of Pharmacy, University of Science and Technology, Ibb, Yemen
| | - Yahiya Kadaf Manea
- Department of Chemistry, Aligarh Muslim University, Aligarh, India; Department of Chemistry, University of Aden, Aden, Yemen.
| | - Ayyaz Mahmood
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
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2
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Yang YD, Lu N, Tian R. Serum albumin acted as an effective carrier to improve the stability of bioactive flavonoid. Amino Acids 2023; 55:1879-1890. [PMID: 37856004 DOI: 10.1007/s00726-023-03347-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 10/03/2023] [Indexed: 10/20/2023]
Abstract
The health-improving functions of bioactive flavonoids in vitro and in vivo are often limited by their low stability, which could be counteracted by the application of proteins as carriers of flavonoids. Clarification of the mechanism of protein-ligand interaction is crucial for the encapsulation of bioactive components. Herein, common plasma proteins [i.e., bovine serum albumin (BSA), human serum albumin (HSA), human immunoglobulin G (IgG) and fibrinogen (FG)] were compared for their binding characteristics to quercetin, the main component of flavonoids in human diet, in the absence and presence of free Cu2+ (an accelerator for flavonoids' instability) using multi-spectroscopic and computational methods. As a flexible open structure of proteins, both BSA and HSA were found to be the most promising carriers for quercetin and Cu2+ with an affinity on the order of 104 M-1. HSA-diligand complex (i.e., HSA-quercetin-Cu2+) was successfully generated when both quercetin and Cu2+ were added to the HSA solution. The stability and free radical scavenging activity of bioactive quercetin during incubation was promoted in the HSA-diligand complex relative to quercetin-Cu2+ complex. Quercetin/Cu2+ system could induce the formation of reactive oxygen species such as hydrogen peroxide (H2O2) and hydroxide radical (·OH), which were significantly suppressed upon HSA binding. Consistently, the cytotoxicity of the quercetin/Cu2+ system to endothelial cells was reduced in the HSA-diligand complex. These results demonstrate the possibility of developing serum albumin-based carriers for the protection of bioactive flavonoids in their nutritional application.
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Affiliation(s)
- Ya-Di Yang
- Jiangxi Key Laboratory of Green Chemistry, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, China
| | - Naihao Lu
- Jiangxi Key Laboratory of Green Chemistry, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, China
| | - Rong Tian
- Jiangxi Key Laboratory of Green Chemistry, College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, China.
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3
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Li L, Gao T, Wu X, Geng M, Teng F, Li Y. Investigation of soybean lipophilic proteins as carriers for vitamin B 12: Focus on interaction mechanism, physicochemical functionality, and digestion characteristics. Food Chem 2023; 424:136435. [PMID: 37244193 DOI: 10.1016/j.foodchem.2023.136435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 04/25/2023] [Accepted: 05/18/2023] [Indexed: 05/29/2023]
Abstract
This study aimed to explore the interaction mechanism between soybean lipophilic protein (LP) and vitamin B12 and the potential of LP as a vitamin B12 carrier. The results of spectroscopy indicated that the interaction between vitamin B12 and LP changed the conformation of LP and exposed hydrophobic groups largely. The results of molecular docking revealed that vitamin B12 interacted with LP through a hydrophobic pocket embedded on the surface of LP. With the enhancement of the interaction between LP and vitamin B12, the particle size of the LP-vitamin B12 complex gradually decreased to 588.31 nm and the absolute value of zeta potential gradually increased to 26.82 mV. Meanwhile, the LP-vitamin B12 complex showed excellent physicochemical properties and digestive characteristics. The present work enriched the means of vitamin B12 protection and provided a theoretical basis for applying the LP-vitamin B12 complex in food systems.
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Affiliation(s)
- Lijia Li
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China
| | - Tian Gao
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China
| | - Xixi Wu
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China
| | - Mengjie Geng
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China
| | - Fei Teng
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
| | - Yang Li
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China; National Research Center of Soybean Engineering and Technology, Harbin, Heilongjiang 150030, China.
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4
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Taniguchi M, LaRocca CA, Bernat JD, Lindsey JS. Digital Database of Absorption Spectra of Diverse Flavonoids Enables Structural Comparisons and Quantitative Evaluations. JOURNAL OF NATURAL PRODUCTS 2023; 86:1087-1119. [PMID: 36848595 DOI: 10.1021/acs.jnatprod.2c00720] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Flavonoids play diverse roles in plants, comprise a non-negligible fraction of net primary photosynthetic production, and impart beneficial effects in human health from a plant-based diet. Absorption spectroscopy is an essential tool for quantitation of flavonoids isolated from complex plant extracts. The absorption spectra of flavonoids typically consist of two major bands, band I (300-380 nm) and band II (240-295 nm), where the former engenders a yellow color; in some flavonoids the absorption tails to 400-450 nm. The absorption spectra of 177 flavonoids and analogues of natural or synthetic origin have been assembled, including molar absorption coefficients (109 from the literature, 68 measured here). The spectral data are in digital form and can be viewed and accessed at http://www.photochemcad.com. The database enables comparison of the absorption spectral features of 12 distinct types of flavonoids including flavan-3-ols (e.g., catechin, epigallocatechin), flavanones (e.g., hesperidin, naringin), 3-hydroxyflavanones (e.g., taxifolin, silybin), isoflavones (e.g., daidzein, genistein), flavones (e.g., diosmin, luteolin), and flavonols (e.g., fisetin, myricetin). The structural features that give rise to shifts in wavelength and intensity are delineated. The availability of digital absorption spectra for diverse flavonoids facilitates analysis and quantitation of these valuable plant secondary metabolites. Four examples are provided of calculations─multicomponent analysis, solar ultraviolet photoprotection, sun protection factor (SPF), and Förster resonance energy transfer (FRET)─for which the spectra and accompanying molar absorption coefficients are sine qua non.
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Affiliation(s)
- Masahiko Taniguchi
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Connor A LaRocca
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jake D Bernat
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jonathan S Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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5
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Zhao J, Huang L, Li R, Zhang Z, Chen J, Tang H. Multispectroscopic and computational evaluation of the binding of flavonoids with bovine serum albumin in the presence of Cu2+. Food Chem 2022; 385:132656. [DOI: 10.1016/j.foodchem.2022.132656] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 03/01/2022] [Accepted: 03/06/2022] [Indexed: 11/29/2022]
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6
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Liu H, Wang D, Ren Y, Wang L, Weng T, Liu J, Wu Y, Ding Z, Liu M. Multispectroscopic and synergistic antioxidant study on the combined binding of caffeic acid and (-)-epicatechin gallate to lysozyme. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 272:120986. [PMID: 35151167 DOI: 10.1016/j.saa.2022.120986] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/07/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
The binding of caffeic acid (CA) and/or (-)-epicatechin gallate (ECG) to lysozyme was investigated by multispectroscopic methods and molecular docking. The effects of the single and combined binding on the structure, activity and stability of lysozyme and the synergistic antioxidant activity of CA and ECG were also studied. Fluorescence quenching spectra, time-resolved fluorescence spectra, and UV-vis absorption difference spectra all ascertained the static quenching mechanism of lysozyme by CA/ECG. Thermodynamic parameters indicated that CA and ECG competitively bound to lysozyme, and CA had a stronger binding affinity, which was consistent with the results of molecular docking. Hydrogen bonding, van der Waals' force and electrostatic interaction were the main driving forces for the binding process. Synchronous fluorescence spectra displayed that the interaction of CA/ECG exposed the tryptophan residues of lysozyme to a more hydrophilic environment. Circular dichroism spectroscopy, Fourier transform infrared spectroscopy and dynamic light scattering indicated that the binding of CA and/or ECG to lysozyme resulted in the change of the secondary structure and increased the particle size of lysozyme. The binding of CA and/or ECG to lysozyme inhibited the enzyme activity and enhanced the thermal stability of lysozyme. The combined application of CA and ECG showed antioxidant synergy which was influenced by the encapsulation of lysozyme and cellular uptake. In summary, this work provides theoretical guidance for lysozyme as a carrier for the combined application of CA and ECG.
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Affiliation(s)
- He Liu
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China
| | - Danfeng Wang
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Yongfang Ren
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Lu Wang
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China
| | - Tianxin Weng
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Jie Liu
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China
| | - Yushu Wu
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Zhuang Ding
- Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China
| | - Min Liu
- School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China; Institute of Biopharmaceutical Research, Liaocheng University, Liaocheng 252059, China.
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7
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Zhou L, Lu N, Pi X, Jin Z, Tian R. Bovine Serum Albumin as a Potential Carrier for the Protection of Bioactive Quercetin and Inhibition of Cu(II) Toxicity. Chem Res Toxicol 2022; 35:529-537. [PMID: 35175047 DOI: 10.1021/acs.chemrestox.2c00001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Considering the protective ability of proteins and the potential toxicity of free Cu(II), it was proposed herein that the co-presence of protein could play an important role in suppressing the toxicity of free Cu(II) to the stability of bioactive quercetin if a flavonoid-protein-Cu(II) complex could be formed. In this study, the interaction between quercetin (a major flavonoid in the human diet) and bovine serum albumin (BSA) was investigated in the absence and presence of free Cu(II). The results demonstrated that both quercetin and free Cu(II) had a strong ability to quench the intrinsic fluorescence of BSA through a static procedure (i.e., formation of a BSA-monoligand complex). Site marker competitive experiments illustrated that the binding of both quercetin and Cu(II) to BSA mainly took place in subdomain IIA. The quenching process of free Cu(II) with BSA was easily affected by quercetin, and the increased binding capacity possibly resulted from the generation of a ternary quercetin-BSA-Cu(II) complex. The stability and free radical scavenging activity of bioactive quercetin during incubation was promoted in the BSA-diligand complex relative to a quercetin-Cu(II) complex. A quercetin-Cu(II) system could generate reactive oxygen species such as hydrogen peroxide (H2O2) and hydroxyl radicals (•OH), which were significantly inhibited upon BSA binding. Consistently, the cytotoxicity of the quercetin-Cu(II) system to endothelial cells was decreased in the BSA-diligand complex, where the co-presence of BSA played an important role. These results suggest the possibility and advantage of developing albumin-based carriers for the protection of bioactive components and suppression of Cu(II) toxicity in their biomedical and nutritional applications.
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Affiliation(s)
- Lan Zhou
- Jiangxi Key Laboratory of Green Chemistry, MOE Key Laboratory of Functional Small Organic Molecule, and College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
| | - Naihao Lu
- Jiangxi Key Laboratory of Green Chemistry, MOE Key Laboratory of Functional Small Organic Molecule, and College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
| | - Xuefen Pi
- Yangxin No. 1 Middle School in Hubei Province, Huangshi, Hubei 435200, China
| | - Zelong Jin
- Jiangxi Key Laboratory of Green Chemistry, MOE Key Laboratory of Functional Small Organic Molecule, and College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
| | - Rong Tian
- Jiangxi Key Laboratory of Green Chemistry, MOE Key Laboratory of Functional Small Organic Molecule, and College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China
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8
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Zare Karizak A, Divsalar A, Leilabadi Asl A, Fateminasab F, Shityakov S, Saboury AA. Molecular insights into the interaction of 5-fluorouracil and Fe 3O 4 nanoparticles with beta-casein: An experimental and theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 267:120538. [PMID: 34749259 DOI: 10.1016/j.saa.2021.120538] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/12/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
We investigated the potential carrier of milk beta-casein (β-CN) and its interactions with 5-fluorouracil (5-FU) and iron oxide nanoparticles (Fe3O4 NPs). We used different spectroscopic methods of fluorescence, UV-Visble, circular dichroism (CD), synchronous fluorescence, zeta potential assay, and computational studies to clarify the protein interaction with 5-FU and Fe3O4 NPs. The fluorescence data indicated both Fe3O4 NPs and 5-FU could quench the intrinsic fluorescence of β-CN. Fluorescence measurements showed that the single interaction of β-CN with 5-FU or Fe3O4 NPs was static, while reacted β-CN with both 5-FU and Fe3O4 NPs simultaneously showed a dynamic quenching. Synchronous fluorescence data in both tests revealed that the tryptophan (Trp) residue of β-CN had a dominant role in quenching and the polarity of its microenvironment more than tyrosine (Tyr) increased in interaction with 5-FU. All the binding sites and thermodynamic parameters were obtained at 25, 37, and 42 °C. The analysis of thermodynamic parameters and Job's plot techniques pointed to that both of these complexes with the 1:1 M ratio were exothermic (ΔH°<0) driven with the van der Waals and H-bonding interactions (in agreement with the docking results). The CD spectra in the region of far-UV and thermal denaturation study indicated minor changes in the secondary structure of β-CN in the presence of various concentrations of Fe3O4 NPs and 5-FU. Also, from the molecular dynamics (MD) analysis, as a result, the protein structure was stable during 100 ns. The outcomes highlighted that β-CN protein could form a great bind with 5-FU and Fe3O4 NPs ligands (supporting the zeta potential assay results) by independent binding sites. These results would be helpful insight to construct a potential magnetic nanocarrier β-CN base for 5-FU drug delivery.
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Affiliation(s)
- Ashkan Zare Karizak
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Adeleh Divsalar
- Department of Cell & Molecular Sciences, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran.
| | - Amineh Leilabadi Asl
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran 1477893855, Iran
| | | | - Sergey Shityakov
- ITMO University, Infochemistry Scientific Center, Division of Chemoinformatics, Saint-Petersburg 191002, Russian Federation
| | - Ali Akbar Saboury
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
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9
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Stevanović N, Apostolović D, Milčić M, Lolić A, van Hage M, Veličković TĆ, Baošić R. Interaction, binding capacity and anticancer properties of N, N′-bis(acetylacetone)-propylenediimine-copper( ii) on colorectal cancer cell line Caco-2. NEW J CHEM 2021. [DOI: 10.1039/d1nj00040c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The binding capacity and interaction of N,N′-bis(acetylacetone)propylenediimine-copper(ii) with HSA were systemically investigated in vitro and in silico.
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Affiliation(s)
| | - Danijela Apostolović
- Immunology and Allergy Divison
- Department of Medicine Solna
- Karolinska Institutet
- Stockholm
- Sweden
| | - Miloš Milčić
- University of Belgrade – Faculty of Chemistry
- Belgrade
- Serbia
| | | | - Marianne van Hage
- Immunology and Allergy Divison
- Department of Medicine Solna
- Karolinska Institutet
- Stockholm
- Sweden
| | - Tanja Ćirković Veličković
- University of Belgrade – Faculty of Chemistry
- Belgrade
- Serbia
- Serbian Academy of Science and Art
- Belgrade
| | - Rada Baošić
- University of Belgrade – Faculty of Chemistry
- Belgrade
- Serbia
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Ionophoric polyphenols are permeable to the blood–brain barrier, interact with human serum albumin and Calf Thymus DNA, and inhibit AChE enzymatic activity. Med Chem Res 2020. [DOI: 10.1007/s00044-020-02615-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sarmah S, Pahari S, Belwal VK, Jana M, Singha Roy A. Elucidation of molecular interaction of bioactive flavonoid luteolin with human serum albumin and its glycated analogue using multi-spectroscopic and computational studies. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114147] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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12
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Sarmah S, Pahari S, Das S, Belwal VK, Jana M, Singha Roy A. Non-enzymatic glycation of human serum albumin modulates its binding efficacy towards bioactive flavonoid chrysin: A detailed study using multi-spectroscopic and computational methods. J Biomol Struct Dyn 2020; 39:476-492. [PMID: 31900044 DOI: 10.1080/07391102.2019.1711196] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The non-enzymatic glycation of plasma proteins by reducing sugars have important consequences on the conformational and functional properties of protein. The formation of advanced glycation end products (AGEs) is responsible for cell death and other pathological conditions. We have synthesized the glycated human serum albumin (gHSA) and characterized the same by using differential spectroscopic measurements. The aim of the present study is to determine the effect of glycation on the binding of human serum albumin (HSA) with bioactive flavonoid chrysin, which possesses anti-cancer, anti-inflammatory and anti-oxidant activities. The interaction of chrysin with HSA and gHSA was studied using multi-spectroscopic, molecular docking and molecular dynamics (MD) simulation techniques. Chrysin quenched the intrinsic fluorescence of both HSA and gHSA by static quenching mechanism. The value of the binding constant (Kb) for the interaction of HSA-chrysin complex (4.779 ± 0.623 × 105 M-1 at 300 K) was found to be higher than that of gHSA-chrysin complex (2.206 ± 0.234 × 105 M-1 at 300 K). Hence, non-enzymatic glycation of HSA significantly reduced its binding affinity towards chrysin. The % α-helicity of HSA was found to get enhanced upon binding with chrysin, and minimal changes were observed for the gHSA-chrysin complex. Site marker probe studies indicated that chrysin binds to subdomain IIA and IIIA of both HSA and gHSA. The results from molecular docking and MD simulation studies correlated well with the experimental findings. Electrostatic interactions followed by hydrogen bonding and hydrophobic interactions played major roles in the binding process. These observations may have some useful insights into the field of pharmaceutics.
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Affiliation(s)
- Sharat Sarmah
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
| | - Somdev Pahari
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela, India
| | - Sourav Das
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
| | - Vinay Kumar Belwal
- Department of Bioscience and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Madhurima Jana
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela, India
| | - Atanu Singha Roy
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
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13
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Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG. Biochem Res Int 2019; 2019:6154170. [PMID: 31827928 PMCID: PMC6881586 DOI: 10.1155/2019/6154170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/23/2019] [Accepted: 09/28/2019] [Indexed: 11/17/2022] Open
Abstract
Label-free detection methods such as the quartz crystal microbalance (QCM) are well suited to the analysis of molecular interactions in complex mixtures such as crude botanical extracts. In the present study, the binding characteristics of epigallocatechin gallate (EGCG) and crude green tea extract solutions to bovine serum albumin (BSA) have been investigated. The adsorbed mass levels onto BSA-functionalized surfaces were measured at various solution concentrations. Langmuir and Freundlich isotherms were used to model the adsorption data. The Langmuir isotherm better described the adsorption behavior with correlations of 0.68 and 0.70 for the EGCG and the crude extract solutions, respectively. The better fit of the Langmuir model indicates that adsorption occurs homogeneously and that aggregation is negligible. The mass saturation is estimated to be 58% higher for the crude green tea solution as compared to the pure EGCG solution (7.9 ng/cm2 for green tea and 5 ng/cm2 for EGCG). The increased adsorption for the crude extract indicates that the additional tea chemical constituents are binding to alternate sites on the protein molecule and that competitive binding is a nondominant effect. However, a reduced adsorption rate for the crude extract was also observed, indicating some presence of competitive mechanisms. The results demonstrate the utility of the QCM for the analysis of protein binding in crude mixtures as well as pure compounds.
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14
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Interaction between an (−)-epigallocatechin-3-gallate-copper complex and bovine serum albumin: Fluorescence, circular dichroism, HPLC, and docking studies. Food Chem 2019; 301:125294. [DOI: 10.1016/j.foodchem.2019.125294] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/26/2019] [Accepted: 07/29/2019] [Indexed: 11/20/2022]
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15
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Chandel TI, Afghani M, Masroor A, Siddique IA, Zakariya SM, Ali M, Khan RH. An insight into the inhibition of fibrillation process verses disaggregation of preformed fibrils of bovine serum albumin by isoprenaline hydrochloride. Int J Biol Macromol 2019; 154:1448-1459. [PMID: 31778695 DOI: 10.1016/j.ijbiomac.2019.11.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/03/2019] [Accepted: 11/05/2019] [Indexed: 01/07/2023]
Abstract
This study is based on the analysis of the recent trend of medication in neurodegenerative diseases. Due to the asymptomatic nature of the diseases, medication delays. Therefore, mechanism of medication assists in removal of the symptoms. Therefore, in order to find out remedy for complete prevention of the disease we have considered "inhibition verses disaggregation" study. Various biophysical techniques such as turbidity measurement (TM), Thioflavin T (ThT) binding assays, circular dichroism (CD), transmission electron microscopy (TEM) etc. has been performed. Isoprenaline hydrochloride (ISO) was a good candidate for inhibition and disaggregation of preformed fibrils of BSA. Therefore, it is concluded that inhibition of fibrillation process was more momentous, effective procedure in restricting the aggregation by stabilizing the native conformation of BSA than the removal of preformed amyloid fibrils under in vitro condition. Forwarding ahead, to understand the efficiency of the two processes under in vivo condition, this study can be applied on animal models so that we can look forward on human beings as well for the development of vaccines. This study is concerned about the applied aspect of research in future so that we can hope for prevention of the disease instead of only removal of the symptoms.
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Affiliation(s)
- Tajalli Ilm Chandel
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, U.P., India
| | - Mariyam Afghani
- Schools of Life Sciences, Devi Ahilya Vishwavidyalaya, Takshila campus, Bhawarkua, Khandwa road, Indore, M.P., India
| | - Aiman Masroor
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, U.P., India
| | | | | | - Maroof Ali
- Moradabad Institutes of Technology, Moradabad, U.P., India
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, U.P., India.
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Najaran A, Divsalar A, Saboury AA, Roodbari NH. Probing the Interaction of Newly Synthesized Pt(II) Complex on Human Serum Albumin Using Competitive Binding Site Markers. J Fluoresc 2019; 29:827-835. [DOI: 10.1007/s10895-019-02383-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/17/2019] [Indexed: 10/26/2022]
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17
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Das S, Santra S, Rohman MA, Ray M, Jana M, Singha Roy A. An insight into the binding of 6-hydroxyflavone with hen egg white lysozyme: a combined approach of multi-spectroscopic and computational studies. J Biomol Struct Dyn 2018; 37:4019-4034. [DOI: 10.1080/07391102.2018.1535451] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Sourav Das
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
| | - Santanu Santra
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela, India
| | - Mostofa Ataur Rohman
- Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong, India
| | - Mahuah Ray
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
| | - Madhurima Jana
- Molecular Simulation Laboratory, Department of Chemistry, National Institute of Technology, Rourkela, India
| | - Atanu Singha Roy
- Department of Chemistry, National Institute of Technology, Meghalaya, Shillong, India
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Das S, Khanikar P, Hazarika Z, Rohman MA, Uzir A, Nath Jha A, Singha Roy A. Deciphering the Interaction of 5,7-Dihydroxyflavone with Hen-Egg-White Lysozyme through Multispectroscopic and Molecular Dynamics Simulation Approaches. ChemistrySelect 2018. [DOI: 10.1002/slct.201800280] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sourav Das
- Department of Chemistry; National Institute of Technology; Meghalaya 793003 India
| | - Portia Khanikar
- Department of Chemistry; National Institute of Technology; Meghalaya 793003 India
| | - Zaved Hazarika
- Department of Molecular Biology and Biotechnology; Tezpur University; Tezpur 784028 India
| | - Mostofa Ataur Rohman
- Centre for Advanced Studies; Department of Chemistry; North-Eastern Hill University; Shillong 793022 India
| | - Antara Uzir
- Department of Chemistry; National Institute of Technology; Meghalaya 793003 India
| | - Anupam Nath Jha
- Department of Molecular Biology and Biotechnology; Tezpur University; Tezpur 784028 India
| | - Atanu Singha Roy
- Department of Chemistry; National Institute of Technology; Meghalaya 793003 India
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Das S, Karn A, Sarmah R, Rohman MA, Koley S, Ghosh P, Roy AS. Characterization of non-covalent binding of 6-hydroxyflavone and 5,7-dihydroxyflavone with bovine hemoglobin: Multi-spectroscopic and molecular docking analyses. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2018; 178:40-52. [DOI: 10.1016/j.jphotobiol.2017.10.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/19/2017] [Accepted: 10/24/2017] [Indexed: 11/25/2022]
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20
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Bagherpour Zarchi M, Divsalar A, Abrari K, Rezaei A. Multiple spectroscopic studies of the interaction between a quaternary ammonium-based cationic Gemini surfactant (as a carrier) and human erythropoietin. J Biomol Struct Dyn 2017; 36:3479-3486. [DOI: 10.1080/07391102.2017.1391123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
| | - Adeleh Divsalar
- Department of Cell & Molecular Sciences, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | | | - Arezou Rezaei
- School of Biology, Damghan University, Damghan, Iran
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21
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Ansari SS, Khan RH, Naqvi S. Probing the intermolecular interactions into serum albumin and anthraquinone systems: a spectroscopic and docking approach. J Biomol Struct Dyn 2017; 36:3362-3375. [DOI: 10.1080/07391102.2017.1388284] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Sameer Shakeel Ansari
- Department of Chemistry, Aligarh Muslim University, Aligarh, 202 002, Uttar Pradesh, India
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202 002, Uttar Pradesh, India
| | - Saeeda Naqvi
- Department of Chemistry, Aligarh Muslim University, Aligarh, 202 002, Uttar Pradesh, India
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22
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Roy AS, Samanta SK, Ghosh P, Tripathy DR, Ghosh SK, Dasgupta S. Cell cytotoxicity and serum albumin binding capacity of the morin-Cu(ii) complex and its effect on deoxyribonucleic acid. MOLECULAR BIOSYSTEMS 2017; 12:2818-33. [PMID: 27345944 DOI: 10.1039/c6mb00344c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The dietary components, flavonoids, are important for their anti-oxidant properties and the ability to act as metal ion chelators. The characterization of the morin-Cu(ii) complex is executed using elemental analysis, FTIR and mass spectroscopy. DNA cleaving and cell cytotoxicity properties followed by serum albumin binding have been investigated in this report. The morin-Cu(ii) complex was found to cleave plasmid pBR322 DNA via an oxidative pathway as revealed by agarose gel based assay performed in the presence of some scavengers and reactive oxygen species. The breaking of the deoxyribose ring of calf thymus DNA (ct-DNA) was also confirmed by the formation of thiobarbituric acid reacting species (TBARS) between thiobarbituric acid and malonaldehyde. The morin-Cu(ii) complex is able to inhibit the growth of human HeLa cells. Fluorescence studies revealed that the morin-Cu(ii) complex can quench the intrinsic fluorescence of serum albumins (SAs) via a static quenching method. The binding constants were found to be in the order of 10(5) M(-1) and observed to increase with temperature. Both ΔH° and ΔS° are positive for the binding of the morin-Cu(ii) complex with serum albumins which indicated the presence of hydrophobic forces. Site-selectivity studies reveal that the morin-Cu(ii) complex binds to both site 1 (subdomain IIA) and site 2 (subdomain IIIA) of human serum albumin (HSA) and bovine serum albumin (BSA). Circular dichroism (CD) studies showed the structural perturbation of SAs during binding with the morin-Cu(ii) complex. The results from binding studies confirmed that after complexation with the Cu(ii) ion, morin alters its mode of interaction with SAs which could have differential implications on its other biological and pharmaceutical properties.
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Affiliation(s)
- Atanu Singha Roy
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
| | - Sintu Kumar Samanta
- Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, India
| | - Pooja Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
| | - Debi Ranjan Tripathy
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
| | - Sudip Kumar Ghosh
- Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, India
| | - Swagata Dasgupta
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
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Zhang L, Sahu ID, Xu M, Wang Y, Hu X. Effect of metal ions on the binding reaction of (−)-epigallocatechin gallate to β-lactoglobulin. Food Chem 2017; 221:1923-1929. [DOI: 10.1016/j.foodchem.2016.11.158] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 10/26/2016] [Accepted: 11/30/2016] [Indexed: 11/25/2022]
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24
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Chandel TI, Rabbani G, Khan M, Zaman M, Alam P, E. Shahein Y, Hasan Khan R. Binding of anti-cardiovascular drug to serum albumin: an insight in the light of spectroscopic and computational approaches. J Biomol Struct Dyn 2016; 36:54-67. [DOI: 10.1080/07391102.2016.1266968] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tajalli Ilm Chandel
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Gulam Rabbani
- School of Medical Biotechnology, YeungNam University, Gyeongsan, Republic of Korea
| | - MohsinVahid Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Masihuz Zaman
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Parvez Alam
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Yasser E. Shahein
- Molecular Biology Department, Genetic Engineering Division, National Research Centre, Cairo, Egypt
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
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Glycation of human serum albumin affects its binding affinity towards (−)-epigallocatechin gallate. J INCL PHENOM MACRO 2016. [DOI: 10.1007/s10847-016-0619-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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26
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Dymerski T, Namieśnik J, Leontowicz H, Leontowicz M, Vearasilp K, Martinez-Ayala AL, González-Aguilar GA, Robles-Sánchez M, Gorinstein S. Chemistry and biological properties of berry volatiles by two-dimensional chromatography, fluorescence and Fourier transform infrared spectroscopy techniques. Food Res Int 2016. [DOI: 10.1016/j.foodres.2016.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Roy AS, Dinda AK, Pandey NK, Dasgupta S. Effects of urea, metal ions and surfactants on the binding of baicalein with bovine serum albumin. J Pharm Anal 2016; 6:256-267. [PMID: 29403991 PMCID: PMC5762607 DOI: 10.1016/j.jpha.2016.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 04/01/2016] [Accepted: 04/05/2016] [Indexed: 11/19/2022] Open
Abstract
The interaction of baicalein with bovine serum albumin (BSA) was investigated with the help of spectroscopic and molecular docking studies. The binding affinity of baicalein towards BSA was estimated to be in order of 105 M−1 from fluorescence quenching studies. Negative ΔH° (−5.66±0.14 kJ/mol) and positive (ΔS°) (+79.96±0.65 J/mol K) indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°. The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate (SDS) due to probable hydrophobic association of baicalein with SDS, resulting in a negative ΔS° (−40.65±0.87 J/mol K). Matrix-assisted laser desorption ionization/time of flight (MALDI--TOF) experiments indicate a 1:1 complexation between baicalein and BSA. The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements. It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA. The presence of metal ions (Ag+, Mg2+, Ni2+, Mn2+, Co2+and Zn2+) increased the binding affinity of ligand towards BSA. The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopic techniques. Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1 (subdomain IIA) of BSA.
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Affiliation(s)
- Atanu Singha Roy
- Correspondence to: Department of Chemistry, National Institute of Technology Meghalaya, Shillong 793003, India.Department of Chemistry, National Institute of Technology MeghalayaShillong793003India
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Roy AS, Tripathy DR, Samanta S, Ghosh SK, Dasgupta S. DNA damaging, cell cytotoxicity and serum albumin binding efficacy of the rutin–Cu(ii) complex. MOLECULAR BIOSYSTEMS 2016; 12:1687-701. [DOI: 10.1039/c6mb00161k] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rutin–Cu(ii) complex causes DNA damage and is also able to inhibit the growth of human HeLa cells. This complex binds with serum albuminsviahydrophobic forces.
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Affiliation(s)
- Atanu Singha Roy
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | | | - Sintu Samanta
- Department of Biotechnology
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Sudip K. Ghosh
- Department of Biotechnology
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Swagata Dasgupta
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
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Singha Roy A, Ghosh P, Dasgupta S. Glycation of human serum albumin alters its binding efficacy towards the dietary polyphenols: a comparative approach. J Biomol Struct Dyn 2015; 34:1911-8. [DOI: 10.1080/07391102.2015.1094749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Atanu Singha Roy
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Pooja Ghosh
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
| | - Swagata Dasgupta
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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Characterization of the binding of flavanone hesperetin with chicken egg lysozyme using spectroscopic techniques: effect of pH on the binding. J INCL PHENOM MACRO 2015. [DOI: 10.1007/s10847-015-0578-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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31
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Divsalar A, Khodabakhshian S. Probing the binding site of a new synthesized anti-cancer compound to HSA via competitive ligand binding method. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2015.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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32
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Singha Roy A, Utreja J, Badhei S. Characterization of the binding of fisetin and morin with chicken egg lysozyme using spectroscopic and molecular docking methods. J INCL PHENOM MACRO 2014. [DOI: 10.1007/s10847-014-0465-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Pandey NK, Ghosh S, Nagy NV, Dasgupta S. Fibrillation of human serum albumin shows nonspecific coordination on stoichiometric increment of Copper(II). J Biomol Struct Dyn 2013; 32:1366-78. [DOI: 10.1080/07391102.2013.819300] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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34
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Singha Roy A, Pandey NK, Dasgupta S. Preferential binding of fisetin to the native state of bovine serum albumin: spectroscopic and docking studies. Mol Biol Rep 2013; 40:3239-53. [PMID: 23277393 DOI: 10.1007/s11033-012-2399-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/17/2012] [Indexed: 11/25/2022]
Abstract
We have investigated the binding of the biologically important flavonoid fisetin with the carrier protein bovine serum albumin using multi-spectroscopic and molecular docking methods. The binding constants were found to be in the order of 10(4) M(-1) and the number of binding sites was determined as one. MALDI-TOF analyses showed that one fisetin molecule binds to a single bovine serum albumin (BSA) molecule which is also supported by fluorescence quenching studies. The negative Gibbs free energy change (∆G°) values point to a spontaneous binding process which occurs through the presence of electrostatic forces with hydrophobic association that results in a positive entropy change (+51.69 ± 1.18 J mol(-1) K(-1)). The unfolding and refolding of BSA in urea have been studied in absence and presence of fisetin using steady-state fluorescence and lifetime measurements. Urea denaturation studies indicate that fisetin is gradually released from its binding site on the protein. In the absence of urea, an increase in temperature that causes denaturation of the protein results in the release of fisetin from its bound state indicating that fisetin binds only to the native state of the protein. The circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopic studies showed an increase in % α-helix content of BSA after binding with fisetin. Site marker displacement studies in accordance with the molecular docking results suggested that fisetin binds in close proximity of the hydrophobic cavity in site 1 (subdomain IIA) of the protein. The PEARLS (Program of Energetic Analysis of Receptor Ligand System) has been used to estimate the interaction energy of fisetin with BSA and the results are in good correlation with the experimental findings.
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Affiliation(s)
- Atanu Singha Roy
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India
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