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Ruiz Díaz N, Cisternas C, Silva M, Hernández A, Chacana P. Characterization of anti-soybean agglutinin (SBA) IgY antibodies: a new strategy for neutralization of the detrimental biological activity of SBA. Front Vet Sci 2024; 11:1382510. [PMID: 38681857 PMCID: PMC11045903 DOI: 10.3389/fvets.2024.1382510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 03/20/2024] [Indexed: 05/01/2024] Open
Abstract
Anti-soybean agglutinin (SBA) IgY was produced, and its potential to neutralize the haemagglutinating activity of SBA in vitro was tested. Thirty-five-week-old hens [treatment (n = 5) and control (n = 5)] were immunized with SBA or injected with saline 4 times every 15 days. Eggs were collected after the last immunization, and IgY was extracted using the polyethylene glycol (PEG) method. Serum anti-SBA IgY titres in immunized hens increased after the first immunization and reached a plateau between days 45 and 60. In contrast, specific IgY titres in the control group remained at basal levels throughout the evaluation. Average IgY titres were significantly higher in the treatment group on days 15, 30, 45, and 60. Total IgY content in the egg yolk extract was 38.7 ± 1.6 and 37.7 ± 1.5 mg/ml for the treatment and control groups, respectively. The specific anti-SBA IgY titer detected in the egg yolk extract was significantly higher (p < 0.001) for hens in the treatment group compared to the control group, with OD450nm values of 0.98 ± 0.05 and 0.058 ± 0.02, respectively. The specificity of anti-SBA IgY was confirmed by the Western blotting, and the inhibition of SBA-induced haemagglutination in vitro was compared with D-galactose, a known molecule that binds to SBA and blocks its binding to erythrocytes. The inhibition of SBA-induced haemagglutination by the anti-SBA IgY reached 512 units of haemagglutination inhibition (UHI), compared to 8 or 256 UHI, respectively, when IgY from control chickens or D-galactose was used. Thus, anti-SBA IgY antibodies were efficiently produced in large quantities and effectively inhibited SBA-induced haemagglutination in vitro.
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Affiliation(s)
- Nancy Ruiz Díaz
- Programa de Doctorado en Ciencias Agropecuarias, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
- Escuela de Medicina Veterinaria, Facultad de Recursos Naturales y Medicina Veterinaria, Universidad Santo Tomás, Temuco, Chile
| | - Carlos Cisternas
- Escuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomás, Temuco, Chile
| | - Mauricio Silva
- Departamento de Ciencias Veterinarias y Salud Pública, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
- Núcleo de Investigación en Producción Agroalimentaria, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
| | - Adrián Hernández
- Núcleo de Investigación en Producción Agroalimentaria, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
- Departamento de Ciencias Agropecuarias y Acuícolas, Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
| | - Pablo Chacana
- Instituto de Patobiología, Instituto Nacional de Tecnología Agropecuaria, Buenos Aires, Argentina
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2
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Yuba E, Gupta RK. Preparation of glycopeptide-modified pH-sensitive liposomes for promoting antigen cross-presentation and induction of antigen-specific cellular immunity. Biomater Sci 2024; 12:1490-1501. [PMID: 38329387 DOI: 10.1039/d3bm01746j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Cross-presentation, exogenous antigen presentation onto major histocompatibility complex class I molecules on antigen presenting cells, is crucially important for inducing antigen-specific cellular immune responses for cancer immunotherapy and for the treatment of infectious diseases. One strategy to induce cross-presentation is cytosolic delivery of an exogenous antigen using fusogenic or endosomolytic molecule-introduced nanocarriers. Earlier, we reported liposomes modified with pH-responsive polymers to achieve cytosolic delivery of an antigen. Polyglycidol-based or polysaccharide-based pH-responsive polymers can provide liposomes with delivery performance of antigenic proteins into cytosol via membrane fusion with endosomes responding to acidic pH, leading to induction of cross-presentation. Mannose residue was introduced to pH-responsive polysaccharides to increase uptake selectivity to antigen presenting cells and to improve cross-presentation efficiency. However, direct introduction of mannose residue into pH-responsive polysaccharides suppressed cytoplasmic delivery performance of liposomes. To avoid such interference, for this study, mannose-containing glycans were incorporated separately into pH-responsive polysaccharide-modified liposomes. Soybean agglutinin-derived glycopeptide was used as a ligand for lectins on antigen presenting cells. Incorporation of glycopeptide significantly increased the cellular uptake of liposomes by dendritic cell lines and increased cross-presentation efficiency. Liposomes incorporated both glycopeptide and pH-responsive polysaccharides exhibited strong adjuvant effects in vitro and induced the increase of dendritic cells, M1 macrophages, and effector T cells in the spleen. Subcutaneous administration of these liposomes induced antigen-specific cellular immunity, resulting in strong therapeutic effects in tumor-bearing mice. These results suggest that separate incorporation of glycopeptides and pH-responsive polysaccharides into antigen-loaded liposomes is an effective strategy to produce liposome-based nanovaccines to achieve antigen cross-presentation and induction of cellular immunity towards cancer immunotherapy.
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Affiliation(s)
- Eiji Yuba
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 5998531, Japan.
| | - Rajesh Kumar Gupta
- Protein Biochemistry Research Centre, Dr D. Y. Patil Biotechnology and Bioinformatics Institute, Dr D. Y. Patil Vidyapeeth, Tathawade, Pune 411033, Maharashtra, India.
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3
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Schilling KM, Jorwal P, Ubilla-Rodriguez NC, Assafa TE, Gatdula JRP, Vultaggio JS, Harris DA, Millhauser GL. N-glycosylation is a potent regulator of prion protein neurotoxicity. J Biol Chem 2023; 299:105101. [PMID: 37507020 PMCID: PMC10469999 DOI: 10.1016/j.jbc.2023.105101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/05/2023] [Accepted: 07/25/2023] [Indexed: 07/30/2023] Open
Abstract
The C-terminal domain of the cellular prion protein (PrPC) contains two N-linked glycosylation sites, the occupancy of which impacts disease pathology. In this study, we demonstrate that glycans at these sites are required to maintain an intramolecular interaction with the N-terminal domain, mediated through a previously identified copper-histidine tether, which suppresses the neurotoxic activity of PrPC. NMR and electron paramagnetic resonance spectroscopy demonstrate that the glycans refine the structure of the protein's interdomain interaction. Using whole-cell patch-clamp electrophysiology, we further show that cultured cells expressing PrP molecules with mutated glycosylation sites display large, spontaneous inward currents, a correlate of PrP-induced neurotoxicity. Our findings establish a structural basis for the role of N-linked glycans in maintaining a nontoxic, physiological fold of PrPC.
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Affiliation(s)
- Kevin M Schilling
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA
| | - Pooja Jorwal
- Department of Biochemistry, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA
| | | | - Tufa E Assafa
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA
| | - Jean R P Gatdula
- Department of Biochemistry, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA
| | - Janelle S Vultaggio
- Department of Biochemistry, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA
| | - David A Harris
- Department of Biochemistry, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA.
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California, USA.
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4
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Jang H, Lee C, Hwang Y, Lee SJ. Concanavalin A: coordination diversity to xenobiotic metal ions and biological consequences. Dalton Trans 2021; 50:17817-17831. [PMID: 34806716 DOI: 10.1039/d1dt03501k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The binding ability of lectins has gained attention owing to the carbohydrate-specific interactions of these proteins. Such interactions can be applied to diverse fields of biotechnology, including the detection, isolation, and concentration of biological target molecules. The physiological aspects of the lectin concanavalin A (ConA) have been intensively studied through structural and functional investigations. X-ray crystallography studies have proven that ConA has two β-sheets and a short α-helix and that it exists in the form of a metalloprotein containing Mn2+ and Ca2+. These heterometals are coordinated with side chains located in a metal-coordinated domain (MCD), and they affect the structural environment in the carbohydrate-binding domain (CBD), which interacts with carbohydrates through hydrogen bonds. Recent studies have shown that ConA can regulate biophysical interactions with glycoproteins in virus envelopes because it specifically interacts with diverse polysaccharides through its CBD (Tyr, Asn, Asp, and Arg residues positioned next to the MCD). Owing to their protein-protein interaction abilities, ConA can form diverse self-assembled complexes including monomers, dimers, trimers, and tetramers, thus affording unique results in different applications. In this regard, herein, we present a review of the structural modifications in ConA through metal-ion coordination and their effect on complex formation. In recent approaches, ConA has been applied for viral protein detection, on the basis of the interactions of ConA. These aspects indicate that lectins should be thoroughly investigated with respect to their biophysical interactions, for avoiding unexpected changes in their interaction abilities.
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Affiliation(s)
- Hara Jang
- Department of Chemistry and Institute for Molecular Biology and Genetics, Jeonbuk National University, Jeonju 54896, Republic of Korea.
| | - Chaemin Lee
- Department of Chemistry and Institute for Molecular Biology and Genetics, Jeonbuk National University, Jeonju 54896, Republic of Korea.
| | - Yunha Hwang
- Department of Chemistry and Institute for Molecular Biology and Genetics, Jeonbuk National University, Jeonju 54896, Republic of Korea.
| | - Seung Jae Lee
- Department of Chemistry and Institute for Molecular Biology and Genetics, Jeonbuk National University, Jeonju 54896, Republic of Korea.
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Tsouka A, Hoetzel K, Mende M, Heidepriem J, Paris G, Eickelmann S, Seeberger PH, Lepenies B, Loeffler FF. Probing Multivalent Carbohydrate-Protein Interactions With On-Chip Synthesized Glycopeptides Using Different Functionalized Surfaces. Front Chem 2021; 9:766932. [PMID: 34778215 PMCID: PMC8589469 DOI: 10.3389/fchem.2021.766932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/11/2021] [Indexed: 01/01/2023] Open
Abstract
Multivalent ligand-protein interactions are a commonly employed approach by nature in many biological processes. Single glycan-protein interactions are often weak, but their affinity and specificity can be drastically enhanced by engaging multiple binding sites. Microarray technology allows for quick, parallel screening of such interactions. Yet, current glycan microarray methodologies usually neglect defined multivalent presentation. Our laser-based array technology allows for a flexible, cost-efficient, and rapid in situ chemical synthesis of peptide scaffolds directly on functionalized glass slides. Using copper(I)-catalyzed azide-alkyne cycloaddition, different monomer sugar azides were attached to the scaffolds, resulting in spatially defined multivalent glycopeptides on the solid support. Studying their interaction with several different lectins showed that not only the spatially defined sugar presentation, but also the surface functionalization and wettability, as well as accessibility and flexibility, play an essential role in such interactions. Therefore, different commercially available functionalized glass slides were equipped with a polyethylene glycol (PEG) linker to demonstrate its effect on glycan-lectin interactions. Moreover, different monomer sugar azides with and without an additional PEG-spacer were attached to the peptide scaffold to increase flexibility and thereby improve binding affinity. A variety of fluorescently labeled lectins were probed, indicating that different lectin-glycan pairs require different surface functionalization and spacers for enhanced binding. This approach allows for rapid screening and evaluation of spacing-, density-, ligand and surface-dependent parameters, to find optimal lectin binders.
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Affiliation(s)
- Alexandra Tsouka
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Kassandra Hoetzel
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Marco Mende
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Jasmin Heidepriem
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Grigori Paris
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Department of System Dynamics and Friction Physics, Institute of Mechanics, Technical University of Berlin, Berlin, Germany
| | - Stephan Eickelmann
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Peter H. Seeberger
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Bernd Lepenies
- Institute for Immunology and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Felix F. Loeffler
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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Mondal S, Bobbili KB, Paul S, Swamy MJ. DSC and FCS Studies Reveal the Mechanism of Thermal and Chemical Unfolding of CIA17, a Polydisperse Oligomeric Protein from Coccinia Indica. J Phys Chem B 2021; 125:7117-7127. [PMID: 34167304 DOI: 10.1021/acs.jpcb.1c02120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism of thermal and chemical unfolding of Coccinia indica agglutinin (CIA17), a chitooligosacharide-specific phloem exudate lectin, was investigated by biophysical approaches. DSC studies revealed that the unfolding thermogram of CIA17 consists of three components (Tm ∼ 98, 106, and 109 °C), which could be attributed to the dissociation of protein oligomers into constituent dimers, dissociation of the dimers into monomers, and unfolding of the monomers. Intrinsic fluorescence studies on the chemical denaturation by guanidinium thiocyanate and guanidinium chloride indicated the presence of two distinct steps in the unfolding pathway, which could be assigned to dissociation of the dimeric protein into monomers and unfolding of the monomers. Results of fluorescence correlation spectroscopic studies could be interpreted in terms of the following model: CIA17 forms oligomeric structures in a concentration dependent manner, with the protein existing as a monomer below 1 nM concentration but associating to form dimers at higher concentrations (KD ≈ 2.9 nM). The dimers associate to yield tetramers with a KD of ∼50 μM, which further associate to form higher oligomers with further increase in concentration. These results are consistent with the proposed role of CIA17 as a key player in the defense response of the plant against microbes and insects.
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Affiliation(s)
- Saradamoni Mondal
- School of Chemistry, University of Hyderabad, Hyderabad-500 046, India
| | | | - Sumanta Paul
- School of Chemistry, University of Hyderabad, Hyderabad-500 046, India
| | - Musti J Swamy
- School of Chemistry, University of Hyderabad, Hyderabad-500 046, India
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7
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Apolipoprotein E4 exhibits intermediates with domain interaction. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140535. [PMID: 32882410 DOI: 10.1016/j.bbapap.2020.140535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/18/2020] [Accepted: 08/27/2020] [Indexed: 11/23/2022]
Abstract
ApoE4(C112R) is the strongest risk factor for Alzheimer's disease, while apoE3(C112) is considered normal. The C112R substitution is believed to alter the interactions between the N-terminal (NTD) and the C-terminal domain (CTD) leading to major functional differences. Here we investigate how the molecular property of the residue at position 112 affects domain interaction using an array of C112X substitutions with arginine, alanine, threonine, valine, leucine and isoleucine as 'X'. We attempt to determine the free energy of domain interaction (∆GINT) from stabilities of the NTD (∆GNTD) and CTD (∆GCTD) in the full-length apoE, and the stabilities of fragments of the NTD (∆GNTF) and CTD (∆GCTF), using the relationship, ∆GINT = ∆GNTD + ∆GCTD - ∆GNTF - ∆GCTF. We find that although ∆GNTD is strongly dependent on the C112X substitutions, ∆GNTD - ∆GNTF is small. Furthermore, ∆GCTD remains nearly the same as ∆GCTF. Therefore, ∆GINT is estimated to be small and similar for the apoE isoforms. However, stability of domain interaction monitored by urea dependent changes in interdomain Forster Resonance Energy Transfer (FRET) is found to be strongly dependent on C112X substitutions. ApoE4 exhibits the highest mid-point of denaturation of interdomain FRET. To resolve the apparently contradictory observations, we hypothesize that higher interdomain FRET in apoE4 in urea may involve 'intermediate' states. Enhanced fluorescence of bis-ANS and susceptibility to proteolytic cleavage support that apoE4, specifically, the NTD of apoE4 harbor 'intermediates' in both native and mildly denaturing conditions. The intermediates could hold key to the pathological functions of apoE4.
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Nascimento KS, Santiago MQ, Pinto-Junior VR, Osterne VJS, Martins FWV, Nascimento APM, Wolin IAV, Heinrich IA, Martins MGQ, Silva MTL, Lossio CF, Rocha CRC, Leal RB, Cavada BS. Structural analysis of Dioclea lasiocarpa lectin: A C6 cells apoptosis-inducing protein. Int J Biochem Cell Biol 2017; 92:79-89. [DOI: 10.1016/j.biocel.2017.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 12/16/2022]
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9
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Chaotropes trigger conformational rearrangements differently in Concanavalin A. J CHEM SCI 2017. [DOI: 10.1007/s12039-017-1333-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Almeida SMV, Silva LPBG, Lima LRA, Botelho SPS, Lima MDC, Pitta IDR, Beltrão EIC, Carvalho Júnior LB. Dimethyl-2-[(acridin-9-yl)methylidene]-malonate as fluorescent probe for histochemical analysis. Microsc Res Tech 2017; 80:608-614. [DOI: 10.1002/jemt.22837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/23/2016] [Accepted: 12/28/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Sinara Mônica Vitalino Almeida
- Laboratório de Imunopatologia Keizo Asami (LIKA), Departamento de Bioquímica; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
- Faculdade de Ciências, Educação e Tecnologia de Garanhuns (FACETEG); Universidade de Pernambuco (UPE); Garanhuns PE 55290-000 Brazil
| | - Lúcia Patrícia Bezerra Gomes Silva
- Laboratório de Imunopatologia Keizo Asami (LIKA), Departamento de Bioquímica; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Luiza Rayanna Amorim Lima
- Laboratório de Imunopatologia Keizo Asami (LIKA), Departamento de Bioquímica; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Sandra Paula Sarinho Botelho
- Laboratório de Química e Inovação Terapêutica (LQIT), Departamento de Antibióticos; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Maria do Carmo Lima
- Laboratório de Química e Inovação Terapêutica (LQIT), Departamento de Antibióticos; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Ivan da Rocha Pitta
- Núcleo de Pesquisas em Inovação Terapêutica (Nupit), Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Eduardo Isidoro Carneiro Beltrão
- Laboratório de Imunopatologia Keizo Asami (LIKA), Departamento de Bioquímica; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
| | - Luiz Bezerra Carvalho Júnior
- Laboratório de Imunopatologia Keizo Asami (LIKA), Departamento de Bioquímica; Universidade Federal de Pernambuco (UFPE); Recife PE 50670-901 Brazil
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Datta D, J. Swamy M. Fluorescence and circular dichroism studies on the accessibility of tryptophan residues and unfolding of a jacalin-related α- d -galactose-specific lectin from mulberry ( Morus indica ). JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 170:108-117. [DOI: 10.1016/j.jphotobiol.2017.03.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/23/2017] [Accepted: 03/30/2017] [Indexed: 10/19/2022]
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12
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Pinto-Junior VR, Osterne VJS, Santiago MQ, Correia JLA, Pereira-Junior FN, Leal RB, Pereira MG, Chicas LS, Nagano CS, Rocha BAM, Silva-Filho JC, Ferreira WP, Rocha CRC, Nascimento KS, Assreuy AMS, Cavada BS. Structural studies of a vasorelaxant lectin from Dioclea reflexa Hook seeds: Crystal structure, molecular docking and dynamics. Int J Biol Macromol 2017; 98:12-23. [DOI: 10.1016/j.ijbiomac.2017.01.092] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/16/2017] [Accepted: 01/20/2017] [Indexed: 01/15/2023]
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13
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Wu SC, Wang C, Hansen D, Wong SL. A simple approach for preparation of affinity matrices: Simultaneous purification and reversible immobilization of a streptavidin mutein to agarose matrix. Sci Rep 2017; 7:42849. [PMID: 28220817 PMCID: PMC5318860 DOI: 10.1038/srep42849] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 01/18/2017] [Indexed: 11/09/2022] Open
Abstract
SAVSBPM18 is an engineered streptavidin for affinity purification of both biotinylated biomolecules and recombinant proteins tagged with streptavidin binding peptide (SBP) tags. To develop a user-friendly approach for the preparation of the SAVSBPM18-based affinity matrices, a designer fusion protein containing SAVSBPM18 and a galactose binding domain was engineered. The galactose binding domain derived from the earthworm lectin EW29 was genetically modified to eliminate a proteolytic cleavage site located at the beginning of the domain. This domain was fused to the C-terminal end of SAVSBPM18. It allows the SAVSBPM18 fusions to bind reversibly to agarose and can serve as an affinity handle for purification of the fusion. Fluorescently labeled SAVSBPM18 fusions were found to be stably immobilized on Sepharose 6B-CL. The enhanced immobilization capability of the fusion to the agarose beads results from the avidity effect mediated by the tetrameric nature of SAVSBPM18. This approach allows the consolidation of purification and immobilization of SAVSBPM18 fusions to Sepharose 6B-CL in one step for affinity matrix preparation. The resulting affinity matrix has been successfully applied to purify both SBP tagged β-lactamase and biotinylated proteins. No significant reduction in binding capacity of the column was observed for at least six months.
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Affiliation(s)
- Sau-Ching Wu
- Department of Biological Sciences, University of Calgary, 2500 University Dr., N.W. Calgary, Alberta, T2N 1N4, Canada
| | - Chris Wang
- Department of Biological Sciences, University of Calgary, 2500 University Dr., N.W. Calgary, Alberta, T2N 1N4, Canada
| | - Dave Hansen
- Department of Biological Sciences, University of Calgary, 2500 University Dr., N.W. Calgary, Alberta, T2N 1N4, Canada
| | - Sui-Lam Wong
- Department of Biological Sciences, University of Calgary, 2500 University Dr., N.W. Calgary, Alberta, T2N 1N4, Canada
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Halder S, Surolia A, Mukhopadhyay C. Dynamics simulation of soybean agglutinin (SBA) dimer reveals the impact of glycosylation on its enhanced structural stability. Carbohydr Res 2016; 428:8-17. [DOI: 10.1016/j.carres.2016.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/10/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
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15
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Kameel NIA, Wong YH, Shuib AS, Tayyab S. Conformational analysis of champedak galactose-binding lectin under different urea concentrations. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 98:57-63. [PMID: 26642433 DOI: 10.1016/j.plaphy.2015.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/02/2015] [Accepted: 11/16/2015] [Indexed: 06/05/2023]
Abstract
Conformational analysis of champedak galactose-binding (CGB) lectin under different urea concentrations was studied in phosphate-buffered saline (pH 7.2) using far-ultraviolet circular dichroism (far-UV CD), tryptophan (Trp) fluorescence and ANS fluorescence. In all cases, CGB lectin displayed a two-step, three-state transition. The first transition (from the native state to the intermediate state) started at ∼2.0 M urea and ended at ∼4.5 M urea, while the second transition (from the intermediate state to the completely denatured state) was characterized by the start- and end-points at ∼5.75 M and ∼7.5 M urea, respectively, when analyzed by the emission maximum of Trp fluorescence. A marked increase in the Trp fluorescence, ANS fluorescence and -CD values at 218 nm (-CD218 nm) represented the first transition, whereas a decrease in these parameters defined the second transition. On the other hand, emission maximum of the Trp fluorescence showed a continuous increase throughout the urea concentration range. Transformation of tetramer into monomer represented the first transition, whereas the second transition reflected the unfolding of monomer. Far-UV CD, Trp fluorescence and ANS fluorescence spectra were used to characterize the native, the intermediate and the completely denatured states of CGB lectin, obtained at 0.0 M, 5.0 M and 9.0 M urea, respectively. The intermediate state was characterized by the presence of higher secondary structures, increased ANS binding as well as increased Trp fluorescence intensity. A gradual decrease in the hemagglutination activity of CGB lectin was observed with increasing urea concentrations, showing complete loss at 4.0 M urea.
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Affiliation(s)
- Nurul Iman Ahamed Kameel
- Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Yin How Wong
- Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Adawiyah Suriza Shuib
- Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Saad Tayyab
- Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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16
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Khan JM, Khan MS, Ali MS, Al-Shabib NA, Khan RH. Cetyltrimethylammonium bromide (CTAB) promote amyloid fibril formation in carbohydrate binding protein (concanavalin A) at physiological pH. RSC Adv 2016. [DOI: 10.1039/c6ra03707k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Low concentration of CTAB provoked cross β-sheet formation whereas high concentrations of CTAB direct to alpha helix induction in Con A.
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Affiliation(s)
- Javed Masood Khan
- Department of Food Science and Nutrition
- Faculty of Food and Agricultural Sciences
- King Saud University
- 2460 Riyadh 11451
- Saudi Arabia
| | - Mohd Shahnawaz Khan
- Protein Research Chair
- Department of Biochemistry
- College of Science
- King Saud University
- Riyadh
| | - Mohd Sajid Ali
- Department of Chemistry
- King Saud University
- Riyadh 11451
- Saudi Arabia
| | - Nasser Abdulatif Al-Shabib
- Department of Food Science and Nutrition
- Faculty of Food and Agricultural Sciences
- King Saud University
- 2460 Riyadh 11451
- Saudi Arabia
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit
- Aligarh Muslim University
- Aligarh
- India
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17
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Impact of glycosylation on stability, structure and unfolding of soybean agglutinin (SBA): an insight from thermal perturbation molecular dynamics simulations. Glycoconj J 2015; 32:371-84. [DOI: 10.1007/s10719-015-9601-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/18/2015] [Accepted: 05/26/2015] [Indexed: 11/26/2022]
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18
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Huang YX, Wu ZJ, Huang BT, Luo M. Pathway and mechanism of pH dependent human hemoglobin tetramer-dimer-monomer dissociations. PLoS One 2013; 8:e81708. [PMID: 24312337 PMCID: PMC3842943 DOI: 10.1371/journal.pone.0081708] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 10/16/2013] [Indexed: 11/18/2022] Open
Abstract
Hemoglobin dissociation is of great interest in protein process and clinical medicine as well as in artificial blood research. However, the pathway and mechanisms of pH-dependent human Hb dissociation are not clear, whether Hb would really dissociate into monomers is still a question. Therefore, we have conducted a multi-technique investigation on the structure and function of human Hb versus pH. Here we demonstrate that tetramer hemoglobin can easily dissociate into dimer in abnormal pH and the tetramer → dimer dissociation is reversible if pH returns to normal physiological value. When the environmental pH becomes more acidic (<6.5) or alkaline (>8.0), Hb can further dissociate from dimer to monomer. The proportion of monomers increases while the fraction of dimers decreases as pH declines from 6.2 to 5.4. The dimer → monomer dissociation is accompanied with series changes of protein structure thus it is an irreversible process. The structural changes in the dissociated Hbs result in some loss of their functions. Both the Hb dimer and monomer cannot adequately carry and release oxygen to the tissues in circulation. These findings provide a comprehensive understanding on the pH-dependent protein transitions of human Hb, give guideline to explain complex protein processes and the means to control protein dissociation or re-association reaction. They are also of practical value in clinical medicine, blood preservation and blood substitute development.
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Affiliation(s)
- Yao-Xiong Huang
- Department of Biomedical Engineering, Ji Nan University, Guang Zhou, China
- * E-mail:
| | - Zheng-Jie Wu
- Department of Biomedical Engineering, Ji Nan University, Guang Zhou, China
| | - Bao-Tian Huang
- Department of Biomedical Engineering, Ji Nan University, Guang Zhou, China
| | - Man Luo
- Department of Biomedical Engineering, Ji Nan University, Guang Zhou, China
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19
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Carbohydrate Binding and Unfolding of Spatholobus parviflorus Lectin: Fluorescence and Circular Dichroism Spectroscopic Study. Appl Biochem Biotechnol 2013; 171:80-92. [DOI: 10.1007/s12010-013-0340-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/17/2013] [Indexed: 02/02/2023]
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20
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Attri P, Venkatesu P. Influence of protic ionic liquids on the structure and stability of succinylated Con A. Int J Biol Macromol 2012; 51:119-28. [DOI: 10.1016/j.ijbiomac.2012.04.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 04/17/2012] [Indexed: 11/25/2022]
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21
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Soybean agglutinin coated PLA particles entrapping candidate vaccines induces enhanced primary and sustained secondary antibody response from single point immunization. Eur J Pharm Sci 2012; 45:282-95. [DOI: 10.1016/j.ejps.2011.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/31/2011] [Accepted: 11/28/2011] [Indexed: 11/22/2022]
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22
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Andrade CA, de Oliveira HP, Oliveira MD, Correia MT, Coelho LC, de Melo CP. Protein unfolding studied by fluorescence methods and electrical impedance spectroscopy: The cases of Cratylia mollis and Concanavalin A. Colloids Surf B Biointerfaces 2011; 88:100-7. [DOI: 10.1016/j.colsurfb.2011.06.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 06/12/2011] [Accepted: 06/13/2011] [Indexed: 11/15/2022]
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23
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Portillo-Téllez M, Bello M, Salcedo G, Gutiérrez G, Gómez-Vidales V, García-Hernández E. Folding and homodimerization of wheat germ agglutinin. Biophys J 2011; 101:1423-31. [PMID: 21943423 PMCID: PMC3177061 DOI: 10.1016/j.bpj.2011.07.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/18/2011] [Accepted: 07/25/2011] [Indexed: 10/17/2022] Open
Abstract
Wheat germ agglutinin (WGA) is emblematic of proteins that specialize in the recognition of carbohydrates. It was the first lectin reported to have a capacity for discriminating between normal and malignant cells. Since then, it has become a preferred model for basic research and is frequently considered in the development of biomedical and biotechnological applications. However, the molecular basis for the structural stability of this homodimeric lectin remains largely unknown, a situation that limits the rational manipulation and modification of its function. In this work we performed a thermodynamic characterization of WGA folding and self-association processes as a function of pH and temperature by using differential scanning and isothermal dilution calorimetry. WGA is monomeric at pH 2, and one of its four hevein-like domains is unfolded at room temperature. Under such conditions, the agglutinin exhibits a fully reversible thermal unfolding that consists of three two-state transitions. At higher pH values, the protein forms weak, nonobligate dimers. This behavior contrasts with that observed for the other plant lectins studied thus far, which form strong, obligate oligomers, indicating a distinctly different molecular basis for WGA function. For dimer formation, the four domains must be properly folded. Nevertheless, depending on the solution conditions, self-association may be coupled with folding of the labile domain. Therefore, dimerization may proceed as a rigid-body-like association or a folding-by-binding event. This hybrid behavior is not seen in other plant lectins. The emerging molecular picture for the WGA assembly highlights the need for a reexamination of existing ligand-binding data in the literature.
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Affiliation(s)
| | - Martiniano Bello
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Guillermo Salcedo
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F., México
| | - Gabriel Gutiérrez
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F., México
| | - Virginia Gómez-Vidales
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F., México
| | - Enrique García-Hernández
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, D.F., México
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24
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Esperante SA, Chemes LB, Sánchez IE, de Prat-Gay G. The respiratory syncytial virus transcription antiterminator M(2-1) is a highly stable, zinc binding tetramer with strong pH-dependent dissociation and a monomeric unfolding intermediate. Biochemistry 2011; 50:8529-39. [PMID: 21877705 DOI: 10.1021/bi200661k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human respiratory syncytial virus M(2-1) transcription antiterminator is an essential elongation factor required by the RNA polymerase for effective transcription beyond the first two nonstructural genes. Its exclusive presence in pneumovirus among all paramyxovirus suggests a unique function within this small genus. With the aim of understanding its biochemical properties, we investigated this α-helical tetramer by making use of a biophysical approach. We found that the tetramer hydrodynamic radius is considerably extended at high ionic strengths and determined its zinc content to be one atom per monomer. Dissociation-unfolding experiments show a fully reversible and concentration-dependent cooperative transition, but secondary and tertiary structural changes are uncoupled at lower protein concentrations. We detect the presence of a monomeric intermediate, which can be classified as a "late molten globule" with substantial secondary and tertiary structure. Global fittings of experiments from three different probes at two M(2-1) concentrations provide a free energy of dissociation-unfolding of -36.8 ± 0.1 kcal mol(-1), corresponding to a tight dissociation constant of 10(-28) M(3) at pH 7.0. The tetramer affinity is strongly governed by pH, with a free energy change of 13 kcal mol(-1) when pH decreases from 7.0 to 5.0 (K(D) = 10(-18) M(3)). The drastic changes that take place within a pH range compatible with a cellular environment strongly suggest a regulatory effect of pH on M(2-1) structure and biochemical properties, likely affecting transcription and interaction with proteins and RNA.
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Affiliation(s)
- Sebastián A Esperante
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and IIBA-Conicet, Patricias Argentinas 435, 1405 Buenos Aires, Argentina
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25
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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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26
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The role of metal ions in substrate recognition and stability of concanavalin A: a molecular dynamics study. Biophys J 2010; 96:21-34. [PMID: 18849415 DOI: 10.1529/biophysj.108.134601] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 09/12/2008] [Indexed: 11/18/2022] Open
Abstract
The binding of carbohydrate substrates to concanavalin A (Canavalia ensiformis agglutinin (ConA)) is essential for its interaction with various glycoproteins. Even though metal ions are known to control the sugar binding ability of legume lectins, the interplay between sugar and metal ion binding to ConA has not been elucidated in a detailed manner at the atomic level. We have carried out long, explicit solvent molecular dynamics simulations for tetrameric, dimeric, and monomeric forms of ConA in both the presence and absence of trimannoside and metal ions. Detailed analyses of these trajectories for various oligomeric forms under different environmental conditions have revealed dynamic conformational changes associated with the demetalization of ConA. We found that demetalization of ConA leads to large conformational changes in the ion binding loop, with some of the loop residues moving as far as 17 A with respect to their positions in the native trimannoside and metal ion-bound crystal structure. However, the ?-sheet core of the protein remains relatively unperturbed. In addition, the high mobility of the ion binding loop results in drifting of the substrates in the absence of bound metal ions. These simulations provide a theoretical rationale for previous experimental observations regarding the abolition of the sugar binding ability upon demetalization. We also found that the amino acid stretches of ConA, having high B-factor values in the crystal structure, show relatively greater mobility in the simulations. The overall agreement of the results of our simulations with various experimental studies suggests that the force field parameters and length of simulations used in our study are adequate to mimic the dynamic structural changes in the ConA protein.
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27
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Batista FAH, Goto LS, Garcia W, de Moraes DI, de Oliveira Neto M, Polikarpov I, Cominetti MR, Selistre-de-Araújo HS, Beltramini LM, Araújo APU. Camptosemin, a tetrameric lectin of Camptosema ellipticum: structural and functional analysis. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2010; 39:1193-205. [DOI: 10.1007/s00249-009-0571-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 12/03/2009] [Accepted: 12/14/2009] [Indexed: 11/25/2022]
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28
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Pozo-Dengra J, Martínez-Rodríguez S, Contreras LM, Prieto J, Andújar-Sánchez M, Clemente-Jiménez JM, Las Heras-Vázquez FJ, Rodríguez-Vico F, Neira JL. Structure and conformational stability of a tetrameric thermostableN-succinylamino acid racemase. Biopolymers 2009; 91:757-72. [DOI: 10.1002/bip.21226] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Soybean Lectin Enhances Biofilm Formation by Bradyrhizobium japonicum in the Absence of Plants. Int J Microbiol 2009; 2009:719367. [PMID: 20016675 PMCID: PMC2775637 DOI: 10.1155/2009/719367] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/13/2008] [Accepted: 03/13/2009] [Indexed: 11/18/2022] Open
Abstract
Soybean lectin (SBL) purified from soybean seeds by affinity chromatography strongly bound to Bradyrhizobium japonicum USDA 110 cell surface. This lectin enhanced biofilm formation by B. japonicum in a concentration-dependent manner. Presence of galactose during biofilm formation had different effects in the presence or absence of SBL. Biofilms were completely inhibited in the presence of both SBL and galactose, while in the absence of SBL, galactose was less inhibitory. SBL was very stable, since its agglutinating activity of B. japonicum cells as well as of human group A+ erythrocytes was resistant to preincubation for one week at 60°C. Hence, we propose that plant remnants might constitute a source of this lectin, which might remain active in soil and thus favor B. japonicum biofilm formation in the interval between soybean crop seasons.
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30
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Molla AR, Maity SS, Ghosh S, Mandal DK. Organization and dynamics of tryptophan residues in tetrameric and monomeric soybean agglutinin: studies by steady-state and time-resolved fluorescence, phosphorescence and chemical modification. Biochimie 2009; 91:857-67. [PMID: 19383525 DOI: 10.1016/j.biochi.2009.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 04/11/2009] [Indexed: 10/20/2022]
Abstract
We have investigated the organization and dynamics of tryptophan residues in tetrameric, monomeric and unfolded states of soybean agglutinin (SBA) by selective chemical modification, steady-state and time-resolved fluorescence, and phosphorescence. Oxidation with N-bromosuccinimide (NBS) modifies two tryptophans (Trp 60 and Trp 132) in tetramer, four (Trp 8, Trp 203 and previous two) in monomer, and all six (Trp 8, Trp 60, Trp 132, Trp 154, Trp 203 and Trp 226) in unfolded state. Utilizing wavelength-selective fluorescence approach, we have observed a red-edge excitation shift (REES) of 10 and 5 nm for tetramer and monomer, respectively. A more pronounced REES (21 nm) is observed after NBS oxidation. These results are supported by fluorescence anisotropy experiments. Acrylamide quenching shows the Stern-Volmer constant (K(SV)) for tetramer, monomer and unfolded SBA being 2.2, 5.0 and 14.6 M(-1), respectively. Time-resolved fluorescence studies exhibit biexponential decay with the mean lifetime increasing along tetramer (1.0 ns) to monomer (1.9 ns) to unfolded (3.6 ns). Phosphorescence studies at 77 K give more structured spectra, with two (0,0) bands at 408.6 (weak) and 413.2 nm for tetramer. However, a single (0,0) band appears at 411.8 and 407.2 nm for monomer and unfolded SBA, respectively. The exposure of hydrophobic surface in SBA monomer has been examined by 8-anilino-1-naphthalenesulfonate (ANS) binding, which shows approximately 20-fold increase in ANS fluorescence compared to that for tetramer. The mean lifetime of ANS also shows a large increase (12.0 ns) upon binding to monomer. These results may provide important insight into the role of tryptophans in the folding and association of SBA, and oligomeric proteins in general.
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Affiliation(s)
- Anisur R Molla
- Department of Chemistry & Biochemistry, Presidency College, 86/1 College Street, Kolkata 700 073, West Bengal, India
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31
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Martínez-Cruz LA, Encinar JA, Kortazar D, Prieto J, Gómez J, Fernández-Millán P, Lucas M, Arribas EA, Fernández JA, Martínez-Chantar ML, Mato JM, Neira JL. The CBS Domain Protein MJ0729 of Methanocaldococcus jannaschii Is a Thermostable Protein with a pH-Dependent Self-Oligomerization. Biochemistry 2009; 48:2760-76. [DOI: 10.1021/bi801920r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Luis Alfonso Martínez-Cruz
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - José A. Encinar
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - Danel Kortazar
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - Jesús Prieto
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - Javier Gómez
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - Pablo Fernández-Millán
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - María Lucas
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - Egoitz Astigarraga Arribas
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - José Andrés Fernández
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - María Luz Martínez-Chantar
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - José M. Mato
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
| | - José Luis Neira
- Unidad de Biología Estructural, CIC bioGUNE, Parque Tecnológico de Vizcaya, Ed. 800, 48160 Derio, Bizkaia, Spain, Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Avda. del Ferrocarril s/n, 03202 Elche (Alicante), Spain, Structural Biology and Biocomputing Programme, Centro Nacional de Investigaciones Oncológicas (CNIO), 28007 Madrid, Spain, Departamento de Química-Física, Universidad del País Vasco UPV-EHU, Lejona, Bizkaia, Spain, Unidad de Metabolómica, CIC bioGUNE, Parque
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32
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Gupta G, Vishveshwara S, Surolia A. Stability of dimeric interface in banana lectin: Insight from molecular dynamics simulations. IUBMB Life 2009; 61:252-60. [DOI: 10.1002/iub.162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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33
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Metal-triggered changes in the stability and secondary structure of a tetrameric dihydropyrimidinase: A biophysical characterization. Biophys Chem 2009; 139:42-52. [DOI: 10.1016/j.bpc.2008.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 10/03/2008] [Accepted: 10/04/2008] [Indexed: 11/23/2022]
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34
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Gupta G, Sinha S, Surolia A. Unfolding energetics and stability of banana lectin. Proteins 2008; 72:754-60. [DOI: 10.1002/prot.21961] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Hansia P, Dev S, Surolia A, Vishveshwara S. Insight into the early stages of thermal unfolding of peanut agglutinin by molecular dynamics simulations. Proteins 2007; 69:32-42. [PMID: 17596827 DOI: 10.1002/prot.21512] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Peanut agglutinin is a homotetrameric nonglycosylated protein. The protein has a unique open quaternary structure. Molecular dynamics simulations have been employed to follow the atomistic details of its unfolding at different temperatures. The early events of the deoligomerization of the protein have been elucidated in the present study. Simulation trajectories of the monomer as well as those of the tetramer have been compared and the tetramer is found to be substantially more stable than its monomeric counterpart. The tetramer shows retention of most of its secondary structure but considerable loss of the tertiary structure at high temperature. This observation implies the generation of a molten globule-like intermediate in the later stages of deoligomerization. The quaternary structure of the protein has weakened to a large extent, but none of the subunits are separated. In addition, the importance of the metal-binding to the stability of the protein structure has also been investigated. Binding of the metal ions not only enhances the local stability of the metal-ion binding loop, but also imparts a global stability to the overall structure. The dynamics of different interfaces vary significantly as probed through interface clusters. The differences are substantially enhanced at higher temperatures. The dynamics and the stability of the interfaces have been captured mainly by cluster analysis, which has provided detailed information on the thermal deoligomerization of the protein.
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Affiliation(s)
- Priti Hansia
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
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36
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Vetri V, Librizzi F, Militello V, Leone M. Effects of succinylation on thermal induced amyloid formation in Concanavalin A. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:733-41. [PMID: 17554534 DOI: 10.1007/s00249-007-0181-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/24/2007] [Accepted: 05/07/2007] [Indexed: 10/23/2022]
Abstract
We have recently shown that upon slight thermal destabilization the legume lectin Concanavalin A may undergo two different aggregation processes, leading, respectively, to amyloid fibrils at high pH and amorphous aggregates at low pH. Here we present an experimental study on the amyloid aggregation of Succinyl Concanavalin A, which is a dimeric active variant of Concanavalin. The results show that, as for the native protein, the fibrillation process appears to be favoured by alkaline pH, far from the isoelectric point of the protein. Moreover, it strongly depends on temperature and requires large conformational changes both at secondary and tertiary structure level. With respect to the native protein, the succinyl derivative forms amyloid fibrils in considerably longer times and with a minor exposure of hydrophobic regions. At physiological conditions, Concanavalin A still displays a sizeable tendency to form amyloid fibril, while the succinyl variant does not. A close correlation was observed between the progress of amyloid formation and a narrowing of the tryptophans fluorescence emission band, indicating a reduction of protein conformational heterogeneity in amyloid fibrils.
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Affiliation(s)
- Valeria Vetri
- Dipartimento di Scienze Fisiche e Astronomiche, Università di Palermo, Via Archirafi 36, Palermo, Italy.
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37
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Dev S, Surolia A. Dynamic light scattering study of peanut agglutinin: size, shape and urea denaturation. J Biosci 2007; 31:551-6. [PMID: 17301492 DOI: 10.1007/bf02708406] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Peanut agglutinin (PNA)is a homotetrameric protein with a unique open quaternary structure. PNA shows non-two state profile in chaotrope induced denaturation. It passes through a monomeric molten globule like state before complete denaturation (Reddy et al 1999). This denaturation profile is associated with the change in hydrodynamic radius of the native protein. Though the molten globule-like state is monomeric in nature it expands in size due to partial denaturation. The size and shape of the native PNA as well as the change in hydrodynamic radius of the protein during denaturation has been studied by dynamic light scattering (DLS). The generation of two species is evident from the profile of hydrodynamic radii. This study also reveals the extent of compactness of the intermediate state.
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Affiliation(s)
- Sagarika Dev
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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38
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Martínez-Rodríguez S, Andújar-Sánchez M, Neira JL, Clemente-Jiménez JM, Jara-Pérez V, Rodríguez-Vico F, Las Heras-Vázquez FJ. Site-directed mutagenesis indicates an important role of cysteines 76 and 181 in the catalysis of hydantoin racemase from Sinorhizobium meliloti. Protein Sci 2007; 15:2729-38. [PMID: 17132860 PMCID: PMC2242435 DOI: 10.1110/ps.062452106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Hydantoin racemase enzyme plays a crucial role in the reaction cascade known as "hydantoinase process." In conjunction with a stereoselective hydantoinase and a stereospecific carbamoylase, it allows the total conversion from D,L-5-monosubstituted hydantoins, with a low rate of racemization, to optically pure D- or L-amino acids. Residues Cys76 and Cys181 belonging to hydantoin racemase from Sinorhizobium meliloti (SmeHyuA) have been proved to be involved in catalysis. Here, we report biophysical data of SmeHyuA Cys76 and Cys181 to alanine mutants, which point toward a two-base mechanism for the racemization of 5-monosubstituted hydantoins. The secondary and the tertiary structure of the mutants were not significantly affected, as shown by circular dichroism. Calorimetric and fluorescence experiments have shown that Cys76 is responsible for recognition and proton retrieval of D-isomers, while Cys181 is responsible for L-isomer recognition and racemization. This recognition process is further supported by measurements of protein stability followed by chemical denaturation in the presence of the corresponding compound.
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Affiliation(s)
- Sergio Martínez-Rodríguez
- Departamento Química Física, Bioquímica y Química Inorgánica, Universidad de Almería, 04120 Almería, Spain
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39
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Sinha S, Surolia A. Attributes of glycosylation in the establishment of the unfolding pathway of soybean agglutinin. Biophys J 2007; 92:208-16. [PMID: 16980353 PMCID: PMC1697847 DOI: 10.1529/biophysj.106.092668] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 08/29/2006] [Indexed: 11/18/2022] Open
Abstract
Soybean agglutinin (gSBA) is a tetrameric legume lectin, each of whose subunits are glycosylated. Earlier studies have shown that this protein shows exceptionally high stability in terms of free energy of unfolding when compared to other proteins from the same family. This article deals with the unfolding reactions of the nonglycosylated recombinant form of the protein rSBA and its comparison with the glycosylated counterpart gSBA. The nonglycosylated form features a lower stability when compared to the glycosylated form. Further, the unfolding pathways in the two are widely different. Although the glycosylated form undergoes a simple two-state unfolding, the nonglycosylated species unfolds via a compact monomeric intermediate that is not a molten globule. Representative isothermal and thermal denaturation profiles show that glycosylation accounts for a stabilization of approximately 9 kcal/mol of the tetramer, whereas the difference in T(m) between the two forms is 26 degrees C. Computational studies on the glycan-protein interactions at the noncanonical interface of the protein show that quite a number of hydrogen bond and hydrophobic interactions stabilize the glycoprotein tetramer.
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Affiliation(s)
- Sharmistha Sinha
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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40
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Vetri V, Canale C, Relini A, Librizzi F, Militello V, Gliozzi A, Leone M. Amyloid fibrils formation and amorphous aggregation in concanavalin A. Biophys Chem 2007; 125:184-90. [PMID: 16934387 DOI: 10.1016/j.bpc.2006.07.012] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Accepted: 07/25/2006] [Indexed: 10/24/2022]
Abstract
We here report an experimental study on the thermal aggregation process of concanavalin A, a protein belonging to the legume lectins family. The aggregation process and the involved conformational changes of the protein molecules were followed by means of fluorescence techniques, light scattering, circular dichroism, zeta potential measurements and atomic force microscopy. Our results show that the aggregation process of concanavalin A may evolve through two distinct pathways leading, respectively, to the formation of amyloids or amorphous aggregates. The relative extent of the two pathways is determined by pH, as amyloid aggregation is favored at high pH values ( approximately 9), while the formation of amorphous aggregates is favored at low pH ( approximately 5). At difference from amorphous aggregation, the formation of amyloid fibrils requires significant conformational changes on the protein, both at secondary and tertiary structural level. To our knowledge, this is the first observation of amyloid fibrils from concanavalin A.
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Affiliation(s)
- Valeria Vetri
- Università di Palermo, Dipartimento di Scienze Fisiche ed Astronomiche, Via Archirafi 36, 90123 Palermo, Italy
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41
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Garcia-Pino A, Buts L, Wyns L, Loris R. Interplay between metal binding and cis/trans isomerization in legume lectins: structural and thermodynamic study of P. angolensis lectin. J Mol Biol 2006; 361:153-67. [PMID: 16824540 DOI: 10.1016/j.jmb.2006.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/30/2006] [Accepted: 06/07/2006] [Indexed: 10/24/2022]
Abstract
The interplay between metal binding, carbohydrate binding activity, stability and structure of the lectin from Pterocarpus angolensis was investigated. Removal of the metals leads to a more flexible form of the protein with significantly less conformational stability. Crystal structures of this metal-free form show significant structural rearrangements, although some structural features that allow the binding of sugars are retained. We propose that substitution of an asparagine residue at the start of the C-terminal beta-strand of the legume lectin monomer hinders the trans-isomerization of the cis-peptide bond upon demetallization and constitutes an intramolecular switch governing the isomer state of the non-proline bond and ultimately the lectin phenotype.
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Affiliation(s)
- Abel Garcia-Pino
- Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel and Department of Molecular and Cellular Interactions, Vlaams Interuniversitair Instituut voor Biotechnologie, Brussel, Belgium.
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42
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Mitra N, Sinha S, Ramya TNC, Surolia A. N-linked oligosaccharides as outfitters for glycoprotein folding, form and function. Trends Biochem Sci 2006; 31:156-63. [PMID: 16473013 DOI: 10.1016/j.tibs.2006.01.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 01/06/2006] [Accepted: 01/30/2006] [Indexed: 01/27/2023]
Abstract
Glycosylation, particularly N-linked glycosylation, profoundly affects protein folding, oligomerization and stability. The increased efficiency of folding of glycosylated proteins could be due to the chaperone-like activity of glycans, which is observed even when the glycan is not attached to the protein. Covalently linked glycans could also facilitate oligomerization by mediating inter-subunit interactions in the protein or stabilizing the oligomer in other ways. Glycosylation also affects the rate of fibril formation in prion proteins: N-glycans reduce the rate of fibril formation, and O-glycans affect the rate either way depending on factors such as position and orientation. It has yet to be determined whether there is any correlation among the sites of glycosylation and the ensuing effect in multiply glycosylated proteins. It is also not apparent whether there is a common pattern in the conservation of glycans in a related family of glycoproteins, but it is evident that glycosylation is a multifaceted post-translational modification. Indeed, glycosylation serves to "outfit" proteins for fold-function balance.
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Affiliation(s)
- Nivedita Mitra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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43
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Pohl WH, Hellmuth H, Hilbert M, Seibel J, Walla PJ. A Two-Photon Fluorescence-Correlation Study of Lectins Interacting with Carbohydrated 20 nm Beads. Chembiochem 2006; 7:268-74. [PMID: 16408309 DOI: 10.1002/cbic.200500246] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We present results of a two-photon fluorescence-correlation study carried out with glycosylated and untreated 20 nm fluorescing spheres that interacted with the carbohydrate-binding proteins soybean agglutinin (SBA) and concanavalin A (Con A). The assay principle allows protein-carbohydrate binding interactions to be determined without protein labeling. This assay might serve as a simple model system for studying physical and chemical interactions between proteins and carbohydrates, for example, at cell or virus surfaces. In experiments with galactosylated 20 nm beads and SBA, several stages of protein-carbohydrate interactions could be clearly distinguished. Initially, only a few lectins bound to the nanospheres. At higher lectin concentrations polymerization occurred, and aggregates consisting of about 2.6 x 10(5) glycosylated nanospheres were formed. At very high lectin concentrations, the degree of polymerization dropped, and the size of single SBA-covered nanospheres increased to approximately 40 nm. When Con A was used instead of SBA, a significantly smaller degree of aggregation (4 x 10(4) spheres) was obtained. Treatment of unglycosylated 20 nm beads with SBA as a negative control sample resulted in a much lower unspecific aggregation (5 x 10(3) spheres). The assay principle can thus help to elucidate relative binding affinities.
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Affiliation(s)
- Wiebke H Pohl
- Max-Planck-Institute for Biophysical Chemistry, Department of Spectroscopy and Photochemical Kinetics, Am Fassberg 11, 37077 Göttingen, Germany
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44
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Sinha S, Surolia A. Oligomerization endows enormous stability to soybean agglutinin: a comparison of the stability of monomer and tetramer of soybean agglutinin. Biophys J 2005; 88:4243-51. [PMID: 15792973 PMCID: PMC1305654 DOI: 10.1529/biophysj.105.061309] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 03/18/2005] [Indexed: 11/18/2022] Open
Abstract
Soybean agglutinin is a tetrameric legume lectin, each of whose subunits are glycosylated. This protein shows a very high degree of stability when compared to the other proteins of the same family. In a previous work, it was shown that the unusual stability of the protein is due to a high degree of subunit interactions. In this study we present the thermodynamic parameters for the stability of soybean agglutinin monomer. The monomeric species is found at pH 2 and below which it is most populated at pH 1.9, as evident from size-exclusion chromatographic and dynamic light scattering studies. The analyses of circular dichroism and fluorescence spectroscopy suggest that the monomer is well folded, and that it has certain characteristic features when compared to its tetrameric counterpart. The conformational stabilities of the tetramer and the monomer at the temperature of their maximum stabilities (310 K) are 59.2 kcal/mol and 9.8 kcal/mol, respectively, indicating that oligomerization contributes significantly to the stability of the native molecule. Also, the T(g) difference for the two forms of the protein is approximately 40 K, whereas the difference in DeltaC(p) is only 1.6 kcal/mol/K. This suggests that the major hydrophobic core is present in the monomer itself, and that oligomerization involves mainly ionic interactions.
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Affiliation(s)
- Sharmistha Sinha
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore
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