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Naser EH, Idries AH, Elmubarak SAA, Dafalla MB, Abdelrahim YE, Abdalrhman EA, Ahmed BM, Osman MEM, Awadallah AKE, Ebrahim RMA, Abdellatif AO, Saad HA, Konozy EHE. Isolation, purification, and characterization of lectins from medicinal plant Combretum glutinosum seeds endowed with analgesic and antiulcer properties. Biochimie 2024:S0300-9084(24)00180-9. [PMID: 39102999 DOI: 10.1016/j.biochi.2024.08.003] [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: 04/19/2024] [Revised: 06/19/2024] [Accepted: 08/02/2024] [Indexed: 08/07/2024]
Abstract
In the pursuit of safer and more effective treatments, there is a growing interest in plant-derived compounds, particularly lectins, because of their diverse pharmacological properties. This study focused on isolating, purifying, and characterizing lectin from Combretum glutinosum seeds (CGSLs) to assess its potential as an analgesic and antiulcer agent. CGSL extraction involved defatting and buffer extraction, followed by purification using ammonium sulfate fractionation and fetuin-agarose affinity column chromatography. The isolectins (iso-CGSLs), each consisting of 60 kDa and 57 kDa heterodimeric subunits, displayed glycoprotein properties with a 40 % neutral sugar content. They exhibited peak activity at 55 °C and remained stable for up to the fifth day at room temperature. The activity exhibited a pH dependence, peaking between 7.5 and 10.5, and all seemingly operated independently of metal ions. CGSL, at optimal doses ranging from 6 to 12 mg/kg, had significant analgesic effects on acetic acid-induced writhing and hot plate tests in mice. Evaluation using 0.7 % acetic acid resulted in notable pain reduction across all doses (P < 0.05). The analgesic effect of lectin was partially reversed by naloxone (a morphine antagonist), indicating partial involvement of the opioid receptor system. Furthermore, CGSL exhibited antiulcer effects in ethanol-induced gastric ulcer models in rats, highlighting its therapeutic potential as a natural alternative for analgesic and antiulcer treatments.
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Affiliation(s)
- Eva H Naser
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
| | - Ahmed H Idries
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
| | | | - Maha B Dafalla
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
| | | | | | - Bashir M Ahmed
- Medicinal, Aromatic Plants and Traditional Medicine Research Institute (MAPTRI), National Center for Research, Khartoum, Sudan
| | | | | | - Reem M A Ebrahim
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan
| | - Ashraf O Abdellatif
- Pharmaceutical Research and Development Centre, Faculty of Pharmacy, Karary University, Omdurman, Sudan
| | - Haseeba A Saad
- Department of Zoology, Faculty of Science, University of Khartoum, Khartoum, Sudan
| | - Emadeldin H E Konozy
- Biotechnology Department, Africa City of Technology, Khartoum, Sudan; Pharmaceutical Research and Development Centre, Faculty of Pharmacy, Karary University, Omdurman, Sudan; Biomedical and Clinical Research Centre (BCRC), College of Health and Allied Sciences (CoHAS), University of Cape Coast, Cape Coast, Ghana.
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Amat T, Assifaoui A, Schmitt C, Saurel R. Importance of binary and ternary complex formation on the functional and nutritional properties of legume proteins in presence of phytic acid and calcium. Crit Rev Food Sci Nutr 2023; 63:12036-12058. [PMID: 35852135 DOI: 10.1080/10408398.2022.2098247] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Nowadays, legumes are considered as a good source of plant-based proteins to replace animal ones. They are more favorable regarding environmental aspects and health benefits, therefore many people consider moving toward a greener diet. Interestingly, recent consumer trends are promoting pea and faba bean as alternatives to soybean. Both are rich in protein and a good source of essential nutrients and minerals (calcium). However, these advantages can be partially impaired due to their high phytic acid content. This natural polyphosphate is a major antinutrient in plant-based foods, as it can bind minerals (particularly calcium) and proteins, thereby reducing their digestibility and subsequent bioavailability. Indeed, complexes formed are insoluble and limiting the absorption of nutrients, thus lowering the nutritional value of pulses. To understand and overcome these issues, the present review will refine specific mechanisms involved in assemblies between these three essential compounds in legumes as soluble/insoluble binary or ternary complexes. Molecular interactions are influenced by the environmental medium including pH, ionic strength and molar concentrations modulating the stability of these complexes during protein extraction. Protein/phytic acid/calcium complexes stability is of high relevance for food processing affecting not only structure but also functional and nutritional properties of proteins in legume-based foods.
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Affiliation(s)
- Tiffany Amat
- Université de Bourgogne Franche-Comté (UBFC), L'Institut Agro Dijon, UMR PAM A 02.102, Dijon, France
| | - Ali Assifaoui
- Université de Bourgogne Franche-Comté (UBFC), L'Institut Agro Dijon, UMR PAM A 02.102, Dijon, France
| | - Christophe Schmitt
- Department of Chemistry, Nestlé Research, Nestlé Institute of Material Sciences, Lausanne 26, Switzerland
| | - Rémi Saurel
- Université de Bourgogne Franche-Comté (UBFC), L'Institut Agro Dijon, UMR PAM A 02.102, Dijon, France
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Yang Y, He S, Zhang Y, Li X, Liu H, Li Q, Cao X, Ye Y, Sun H. Comparison of crude prolamins from seven kidney beans (Phaseolus vulgaris L.) based on composition, structure and functionality. Food Chem 2021; 357:129748. [PMID: 33892353 DOI: 10.1016/j.foodchem.2021.129748] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 03/25/2021] [Accepted: 04/04/2021] [Indexed: 01/04/2023]
Abstract
Ethanol protocol, two-step protocol and enzymatic extraction were used to extract prolamins from seven kidney beans (P. vulgaris L.) compared with Osborne protocol. 70-80% (v/v) ethanol concentrations were beneficial to the extraction, and two-step protocol was conducive to higher prolamin content. Varied protein subunits were observed in electrophoresis profiles, and further differences in composition were identified by LC-MS/MS while potential functions were annotated. Stronger hydrophobicity was found with prolamins enrichment from light speckled kidney bean (LSKB), black speckled kidney bean (BSKB), and red kidney bean (RKB), which was negative correlation with α-helix content based on the principal component analysis (PCA). The crude prolamins from the two kinds of white kidney beans possessed higher sulfhydryl and exhibited better water holding capacity (WHC), while higher oil absorption capacity (OAC) was observed in LSKB, BSKB, and RKB. Compared with zein, kidney bean prolamins could be used as food packaging materials due to hydrophobicity.
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Affiliation(s)
- Yufei Yang
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China
| | - Shudong He
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China.
| | - Yi Zhang
- Department of Food Science and Agricultural Chemistry, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue H9X 3V9, Québec, PR, Canada
| | - Xingjiang Li
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China
| | - Haiyan Liu
- Sichuan Huamei Pharmaceutical Co., Ltd., Chengdu Sanojon Pharmaceutical Group, Chengdu 610045, Sichuan, PR China; Dairy Nutrition and Function, Key Laboratory of Sichuan Province, Chengdu 610000, Sichuan, PR China
| | - Qiming Li
- Dairy Nutrition and Function, Key Laboratory of Sichuan Province, Chengdu 610000, Sichuan, PR China
| | - Xiaodong Cao
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China
| | - Yongkang Ye
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China
| | - Hanju Sun
- School of Food and Biological Engineering, Engineering Research Center of Bio-process of Ministry of Education, Hefei University of Technology, Hefei 230009, Anhui, PR China
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Fattah R, Rashedi H, Yazdian F, Mousavi SB, Fazeli A. Promising insights into the kosmotropic effect of magnetic nanoparticles on proteins: The pivotal role of protein corona formation. Biotechnol Prog 2020; 36:e3051. [PMID: 32692433 DOI: 10.1002/btpr.3051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/05/2020] [Accepted: 07/19/2020] [Indexed: 11/05/2022]
Abstract
Increasing concerns about biosafety of nanoparticles (NPs) has raised the need for detailed knowledge of NP interactions with biological molecules especially proteins. Herein, the concentration-dependent effect of magnetic NPs (MNPs) on bovine serum albumin and hen egg white lysozyme was explored. The X-ray diffraction patterns, zeta potential, and dynamic light scattering measurements together with scanning electron microscopy images were employed to characterize MNPs synthesized through coprecipitation method. Then, we studied the behavior of two model proteins with different surface charges and structural properties on interaction with Fe3 O4 . A thorough investigation of protein-MNP interaction by the help of intrinsic fluorescence at different experimental conditions revealed that affinity of proteins for MNPs is strongly affected by the similarity of protein and MNP surface charges. MNPs exerted structure-making kosmotropic effect on both proteins under a concentration threshold; however, binding strength was found to determine the extent of stabilizing effect as well as magnitude of the concentration threshold. Circular dichroism spectra showed that proteins with less resistance to conformational deformations are more prone to secondary structure changes upon adsorption on MNPs. By screening thermal aggregation of proteins in the presence of Fe3 O4 , it was also found that like chemical stability, thermal stability is influenced to a higher extent in more strongly bound proteins. Overall, this report not only provides an integrated picture of protein-MNP interaction but also sheds light on the molecular mechanism underling this process.
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Affiliation(s)
- Reza Fattah
- Department of Biotechnology, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Hamid Rashedi
- Department of Biotechnology, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Fatemeh Yazdian
- Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | | | - Ahmad Fazeli
- Research and Development Department, Zistdaru Danesh Co, Tehran, Iran.,The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), Tehran, Iran
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Agrawal SB, Ghosh D, Gaikwad SM. Investigation of structural and saccharide binding transitions of Bauhinia purpurea and Wisteria floribunda lectins. Arch Biochem Biophys 2019; 662:134-142. [DOI: 10.1016/j.abb.2018.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/19/2018] [Accepted: 12/03/2018] [Indexed: 11/28/2022]
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Yadav P, Shahane G, Ramasamy S, Sengupta D, Gaikwad S. Structuralfunctional insights and studies on saccharide binding of Sophora japonica seed lectin. Int J Biol Macromol 2016; 91:75-84. [DOI: 10.1016/j.ijbiomac.2016.05.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 05/12/2016] [Accepted: 05/12/2016] [Indexed: 11/26/2022]
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Nag JK, Chahar D, Shrivastava N, Gupta CL, Bajpai P, Chandra D, Misra-Bhattacharya S. Functional attributes of evolutionary conserved Arg45 of Wolbachia (Brugia malayi) translation initiation factor-1. Future Microbiol 2016; 11:195-214. [PMID: 26855259 DOI: 10.2217/fmb.15.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM Wolbachia is a promising antifilarial chemotherapeutic target. Translation initiation factor-1 (Tl IF-1) is an essential factor in prokaryotes. Functional characterization of Wolbachia's novel proteins/enzymes is necessary for the development of adulticidal drugs. MATERIALS & METHODS Mutant, Wol Tl IF-1 R45D was constructed by site directed mutagenesis. Fluorimetry and size exclusion chromatography were used to determine the biophysical characteristics. Mobility shift assay and fluorescence resonance energy transfer were used to investigate the functional aspect of Wol Tl IF-1 with its mutant. RESULTS Both wild and mutant were in monomeric native conformations. Wild exhibits nonspecific binding with ssRNA/ssDNA fragments under electrostatic conditions and showed annealing and displacement of RNA strands in comparison to mutant. CONCLUSION Point mutation impaired RNA chaperone activity of the mutant and its interaction with nucleotides.
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Affiliation(s)
- Jeetendra Kumar Nag
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Department of Biochemistry, Lucknow University, Lucknow (UP) 226007, India
| | - Dhanvantri Chahar
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Academy of Scientific & Innovative Research, Coordination Office, Mathura Road, CRRI, Jasola, New Delhi 110020, India
| | - Nidhi Shrivastava
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India
| | - Chhedi Lal Gupta
- Department of Biosciences, Integral University, Lucknow (UP) 226026, India
| | - Preeti Bajpai
- Department of Biosciences, Integral University, Lucknow (UP) 226026, India
| | - Deepak Chandra
- Department of Biochemistry, Lucknow University, Lucknow (UP) 226007, India
| | - Shailja Misra-Bhattacharya
- Division of Parasitology, CSIR-Central Drug Research Institute, BS 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow (UP) 226031, India.,Academy of Scientific & Innovative Research, Coordination Office, Mathura Road, CRRI, Jasola, New Delhi 110020, India
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Wu J, Zhao C, Lin W, Hu R, Wang Q, Chen H, Li L, Chen S, Zheng J. Binding characteristics between polyethylene glycol (PEG) and proteins in aqueous solution. J Mater Chem B 2014; 2:2983-2992. [PMID: 32261674 DOI: 10.1039/c4tb00253a] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Polymer-protein interactions are crucial for determining the activity of both polymer and protein for many bio-related applications. Poly(ethylene glycol) (PEG) as a well-known antifouling material is often coated on surfaces to form highly solvated brushes, which exhibit excellent protein-repellent properties. However, unlike surface-induced antifouling effects, little is known about the intrinsic PEG-protein interactions in aqueous solution, which is an important yet neglected problem. Here, we investigate the interactions between PEG and proteins in aqueous solution using fluorescence spectroscopy, atomic force microscopy (AFM), and nuclear magnetic resonance (NMR). Two important characteristics, molecular weight of PEG and mass ratio of PEG : protein, are examined to determine the effect of each on PEG-protein interactions as well as binding characteristics between PEG and proteins. In contrast to too long and too short PEG chains, collective results have shown that PEG with optimal molecular weight (MW) is more capable of interacting with proteins, which induces the conformational change of proteins through more stable binding sites and stronger interactions with long chain PEG. Enhanced PEG-protein interactions are likely due to the change of hydrophilicity to amphiphilicity of PEG with increasing MWPEG. In contrast to almost none or weak interactions of PEG surfaces with proteins, this work provides new evidence to demonstrate the existence of interactions between PEG and proteins in aqueous solution, which is important not only for better understanding of the structure-activity relationship of PEG both in solution and on surfaces, but also for the rational design of new PEG-based materials for specific applications.
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Affiliation(s)
- Jiang Wu
- State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China 310027.
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Wu J, Zhao C, Hu R, Lin W, Wang Q, Zhao J, Bilinovich SM, Leeper TC, Li L, Cheung HM, Chen S, Zheng J. Probing the weak interaction of proteins with neutral and zwitterionic antifouling polymers. Acta Biomater 2014; 10:751-60. [PMID: 24120846 DOI: 10.1016/j.actbio.2013.09.038] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 09/24/2013] [Accepted: 09/30/2013] [Indexed: 11/18/2022]
Abstract
Protein-polymer interactions are of great interest in a wide range of scientific and technological applications. Neutral poly(ethylene glycol) (PEG) and zwitterionic poly(sulfobetaine methacrylate) (pSBMA) are two well-known nonfouling materials that exhibit strong surface resistance to proteins. However, it still remains unclear or unexplored how PEG and pSBMA interact with proteins in solution. In this work, we examine the interactions between two model proteins (bovine serum albumin and lysozyme) and two typical antifouling polymers of PEG and pSBMA in aqueous solution using fluorescence spectroscopy, atomic force microscopy and nuclear magnetic resonance. The effect of protein:polymer mass ratios on the interactions is also examined. Collective data clearly demonstrate the existence of weak hydrophobic interactions between PEG and proteins, while there are no detectable interactions between pSBMA and proteins. The elimination of protein interaction with pSBMA could be due to an enhanced surface hydration of zwitterionic groups in pSBMA. New evidence is given to demonstrate the interactions between PEG and proteins, which are often neglected in the literature because the PEG-protein interactions are weak and reversible, as well as the structural change caused by hydrophobic interaction. This work provides a better fundamental understanding of the intrinsic structure-activity relationship of polymers underlying polymer-protein interactions, which are important for designing new biomaterials for biosensor, medical diagnostics and drug delivery applications.
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Affiliation(s)
- Jiang Wu
- State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China; Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Chao Zhao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Rundong Hu
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Weifeng Lin
- State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Qiuming Wang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Jun Zhao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | | | - Thomas C Leeper
- Department of Chemistry, The University of Akron, Akron, OH 44325, USA
| | - Lingyan Li
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Harry M Cheung
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
| | - Shengfu Chen
- State Key Laboratory of Chemical Engineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA.
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Molecular modeling of lectin-like protein from Acacia farnesiana reveals a possible anti-inflammatory mechanism in Carrageenan-induced inflammation. BIOMED RESEARCH INTERNATIONAL 2013; 2013:253483. [PMID: 24490151 PMCID: PMC3893743 DOI: 10.1155/2013/253483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/05/2013] [Accepted: 11/05/2013] [Indexed: 11/17/2022]
Abstract
Acacia farnesiana lectin-like protein (AFAL) is a chitin-binding protein and has been classified as phytohaemagglutinin from Phaseolus vulgaris (PHA). Legume lectins are examples for structural studies, and this family of proteins shows a remarkable conservation in primary, secondary, and tertiary structures. Lectins have ability to reduce the effects of inflammation caused by phlogistic agents, such as carrageenan (CGN). This paper explains the anti-inflammatory activity of AFAL through structural comparison with anti-inflammatory legume lectins. The AFAL model was obtained by molecular modeling and molecular docking with glycan and carrageenan were performed to explain the AFAL structural behavior and biological activity. Pisum sativum lectin was the best template for molecular modeling. The AFAL structure model is folded as a β sandwich. The model differs from template in loop regions, number of β strands and carbohydrate-binding site. Carrageenan and glycan bind to different sites on AFAL. The ability of AFAL binding to carrageenan can be explained by absence of the sixth β -strand (posterior β sheets) and two β strands in frontal region. AFAL can inhibit pathway inflammatory process by carrageenan injection by connecting to it and preventing its entry into the cell and triggers the reaction.
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Ghosh G, Mandal DK. Novel unfolding sequence of banana lectin: Folded, unfolded and natively unfolded-like monomeric states in guanidine hydrochloride. Biochimie 2013; 99:138-45. [PMID: 24316282 DOI: 10.1016/j.biochi.2013.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 11/23/2013] [Indexed: 11/16/2022]
Abstract
The sequence of unfolding events of dimeric banana lectin (Banlec), as induced by guanidine hydrochloride (GdnHCl), has been investigated by size-exclusion HPLC, fluorescence, far-UV CD, low temperature phosphorescence and selective chemical modification. 8-Anilino-1-naphthalenesulfonate (ANS) binding indicates a structured unfolding intermediate which has been characterized as dissociated monomer by size-exclusion chromatography. Interestingly, the unfolding elution pattern reveals two distinct unfolded states. One is a usual random coil. The other represents a novel species having elution behavior and structural compactness (Stokes radius) similar to dissociated monomer but showing no regular secondary structure as determined by far-UV CD, thus resembling a natively unfolded state. N-Bromosuccinimide (NBS) oxidation shows that single tryptophan residue remains unmodified in dissociated monomer intermediate while the same is oxidized in natively unfolded-like species. Such difference in tryptophan environment in these species is supported by acrylamide quenching studies, and phosphorescence results at 77 K which show a blue-shift of (0,0) band from 414.8 nm to 409.2 nm. The present results reveal subtlety of structural characteristics of unfolded states of Banlec in GdnHCl, which provide important insight in protein unfolding reaction.
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Affiliation(s)
- Goutam Ghosh
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India
| | - Dipak K Mandal
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India.
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Molla AR, Mandal DK. Trifluoroethanol-induced conformational change of tetrameric and monomeric soybean agglutinin: role of structural organization and implication for protein folding and stability. Biochimie 2013; 95:204-14. [PMID: 23022144 DOI: 10.1016/j.biochi.2012.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 09/13/2012] [Indexed: 11/23/2022]
Abstract
2,2,2-Trifuoroethanol (TFE)-induced conformational structure change of a β-sheet legume lectin, soybean agglutinin (SBA) has been investigated employing its exclusive structural forms in quaternary (tetramer) and tertiary (monomer) states, by far- and near-UV CD, FTIR, fluorescence, low temperature phosphorescence and chemical modification. Far-UV CD results show that, for SBA tetramer, native atypical β-conformation transforms to a highly α-helical structure, with the helical content reaching 57% in 95% TFE. For SBA monomer, atypical β-sheet first converts to typical β-sheet at low TFE concentration (10%), which then leads to a nonnative α-helix at higher TFE concentration. From temperature-dependent studies (5-60 °C) of TFE perturbation, typical β-sheet structure appears to be less stable than atypical β-sheet and the induced helix entails reduced thermal stability. The heat induced transitions are reversible except for atypical to typical β-sheet conversion. FTIR results reveal a partial α-helix conversion at high protein concentration but with quantitative yield. However, aggregation is detected with FTIR at lower TFE concentration, which disappears in more TFE. Near-UV CD, fluorescence and phosphorescence studies imply the existence of an intermediate with native-like secondary and tertiary structure, which could be related to the dissociation of tetramer to monomer. This has been further supported by concentration dependent far-UV CD studies. Chemical modification with N-bromosuccinimide (NBS) shows that all six tryptophans per monomer are solvent-exposed in the induced α-helical conformation. These results may provide novel and important insights into the perturbed folding problem of SBA in particular, and β-sheet oligomeric proteins in general.
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Affiliation(s)
- Anisur R Molla
- Department of Chemistry and Biochemistry, Presidency University, 86/1 College Street, West Bengal, Kolkata 700 073, India
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Qadeer A, Rabbani G, Zaidi N, Ahmad E, Khan JM, Khan RH. 1-Anilino-8-naphthalene sulfonate (ANS) is not a desirable probe for determining the molten globule state of chymopapain. PLoS One 2012; 7:e50633. [PMID: 23209794 PMCID: PMC3510187 DOI: 10.1371/journal.pone.0050633] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 10/23/2012] [Indexed: 01/22/2023] Open
Abstract
The molten globule (MG) state of proteins is widely detected through binding with 1-anilino-8-naphthalene sulphonate (ANS), a fluorescent dye. This strategy is based upon the assumption that when in molten globule state, the exposed hydrophobic clusters of protein are readily bound by the nonpolar anilino-naphthalene moiety of ANS molecules which then produce brilliant fluorescence. In this work, we explored the acid-induced unfolding pathway of chymopapain, a cysteine proteases from Carica papaya, by monitoring the conformational changes over a pH range 1.0–7.4 by circular dichroism, intrinsic fluorescence, ANS binding, acrylamide quenching, isothermal titration calorimetry (ITC) and dynamic light scattering (DLS). The spectroscopic measurements showed that although maximum ANS fluorescence intensity was observed at pH 1.0, however protein exhibited ∼80% loss of secondary structure which does not comply with the characteristics of a typical MG-state. In contrast at pH 1.5, chymopapain retains substantial amount of secondary structure, disrupted side chain interactions, increased hydrodynamic radii and nearly 30-fold increase in ANS fluorescence with respect to the native state, indicating that MG-state exists at pH 1.5 and not at pH 1.0. ITC measurements revealed that ANS molecules bound to chymopapain via hydrophobic interaction were more at pH 1.5 than at pH 1.0. However, a large number of ANS molecules were also involved in electrostatic interaction with protein at pH 1.0 which, together with hydrophobically interacted molecules, may be responsible for maximum ANS fluorescence. We conclude that maximum ANS-fluorescence alone may not be the criteria for determining the MG of chymopapain. Hence a comprehensive structural analysis of the intermediate is essentially required.
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Affiliation(s)
- Atiyatul Qadeer
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Gulam Rabbani
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Nida Zaidi
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Ejaz Ahmad
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Javed M. Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Rizwan H. Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
- * E-mail:
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Ghosh G, Mandal DK. Differing structural characteristics of molten globule intermediate of peanut lectin in urea and guanidine-HCl. Int J Biol Macromol 2012; 51:188-95. [DOI: 10.1016/j.ijbiomac.2012.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/07/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
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Effect of polyethylene glycols on the alkaline-induced molten globule intermediate of bovine serum albumin. Int J Biol Macromol 2012; 51:97-104. [PMID: 22561740 DOI: 10.1016/j.ijbiomac.2012.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/22/2011] [Accepted: 04/20/2012] [Indexed: 01/13/2023]
Abstract
In the present study, the formation of one molten globule-like unfolding intermediate of bovine serum albumin (BSA) at pH 11.2 has been established with the help of circular dichroism (CD) spectra, fluorescence spectroscopy and 'phase diagram' approach. Additionally, we have shown the conformational changes occurring in the pH 11.2 intermediate of BSA when it was exposed to different molecular weight polyethylene glycols (PEGs) at varying concentrations. When the pH 11.2 intermediate of BSA was treated by PEG 400 there was induction of secondary and non-native tertiary contacts. In case of PEG 8000 and PEG 20,000, the loss in secondary as well as tertiary structure was observed. PEG 8000 and 20,000 altered the conformation of the pH 11.2 intermediate and resulted in its transition to another intermediate state in which the hydrophobic patches were inaccessible.
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Mandal P, Mandal DK. Localization and environment of tryptophans in different structural states of concanavalin A. J Fluoresc 2011; 21:2123-32. [PMID: 21748239 DOI: 10.1007/s10895-011-0913-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 07/04/2011] [Indexed: 10/18/2022]
Abstract
We have investigated the localization and environment of tryptophan residues in different quaternary and conformational states (tetrameric, dimeric, monomeric and unfolded) of metallized and demetallized concanavalin A (ConA) by selective chemical modification, fluorescence, and phosphorescence. ConA has four tryptophan residues (Trp 40, Trp 88, Trp 109 and Trp 182) per subunit. The pattern of oxidation by N-bromosuccinimide (NBS) shows that NBS modifies, in dimer, only Trp 182 which remains inaccessible in tetramer, two (Trp 88 along with Trp 182) in monomer, all four in unfolded form in presence of EDTA, and three (possibly Trp 40 along with Trp 88 and Trp 182) in unfolded form from native or remetallized ConA. Utilizing wavelength-selective fluorescence approach, we have observed a red edge excitation shift (REES) of 6-8 nm for tetramer and dimer. A more pronounced REES (11 nm) is observed for oxidized monomer compared to REES (3 nm) for unoxidized species. Acrylamide quenching shows the Stern-Volmer constant (K(SV)) for dimer, monomer, unfolded ConA and unfolded apo-ConA being 3.8, 5.2, 12.8, 14.0 M(-1), respectively. Phosphorescence studies at 77 K give more structured spectra, with two (0,0) bands at 406.2 (weak) and 413.2 nm for tetramer. However, a single (0,0) band appears at 413.2 for dimer and 412.6 nm for monomer, while the (0,0) band of the oxidized monomer is red shifted to 414.4 nm. These results may provide important insight into subtlety of organization and environment of tryptophans in the context of folding and structural studies of oligomeric proteins including lectins.
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Affiliation(s)
- Pritha Mandal
- Department of Chemistry & Biochemistry, Presidency University, Kolkata 700 073, India
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