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De-Simone SG, Lechuga GC, Napoleão-Pêgo P, Gomes LR, Provance DW, Nirello VD, Sodero ACR, Guedes HLDM. Small Angle X-ray Scattering, Molecular Modeling, and Chemometric Studies from a Thrombin-Like (Lmr-47) Enzyme of Lachesis m. rhombeata Venom. Molecules 2021; 26:3930. [PMID: 34203140 PMCID: PMC8271572 DOI: 10.3390/molecules26133930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/31/2021] [Accepted: 06/06/2021] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Snakebite envenomation is considered a neglected tropical disease, and SVTLEs critical elements are involved in serious coagulopathies that occur on envenoming. Although some enzymes of this group have been structurally investigated, it is essential to characterize other proteins to better understand their unique properties such as the Lachesis muta rhombeata 47 kDa (Lmr-47) venom serine protease. METHODS The structure of Lmr-47 was studied in solution, using SAXS, DLS, CD, and in silico by homology modeling. Molecular docking experiments simulated 21 competitive inhibitors. RESULTS At pH 8.0, Lmr-47 has an Rg of 34.5 ± 0.6 Å, Dmax of 130 Å, and SR of 50 Å, according to DLS data. Kratky plot analysis indicates a rigid shape at pH 8.0. Conversely, the pH variation does not change the center of mass's intrinsic fluorescence, possibly indicating the absence of fluorescent amino acids in the regions affected by pH variation. CD experiments show a substantially random coiled secondary structure not affected by pH. The low-resolution model of Lmr-47 presented a prolate elongated shape at pH 8.0. Using the 3D structure obtained by molecular modeling, docking experiments identified five good and three suitable competitive inhibitors. CONCLUSION Together, our work provided insights into the structure of the Lmr-47 and identified inhibitors that may enhance our understanding of thrombin-like family proteins.
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Affiliation(s)
- Salvatore Giovanni De-Simone
- FIOCRUZ, Center of Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation on Neglected Diseases Population (INCT-IDPN), Rio de Janeiro 21040-900, Brazil; (G.C.L.); (P.N.-P.); (L.R.G.); (D.W.P.J.)
- Department of Cellular and Molecular Biology, Biology Institute, Federal Fluminense University, Niterói 24020-141, Brazil
| | - Guilherme Curty Lechuga
- FIOCRUZ, Center of Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation on Neglected Diseases Population (INCT-IDPN), Rio de Janeiro 21040-900, Brazil; (G.C.L.); (P.N.-P.); (L.R.G.); (D.W.P.J.)
| | - Paloma Napoleão-Pêgo
- FIOCRUZ, Center of Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation on Neglected Diseases Population (INCT-IDPN), Rio de Janeiro 21040-900, Brazil; (G.C.L.); (P.N.-P.); (L.R.G.); (D.W.P.J.)
| | - Larissa Rodrigues Gomes
- FIOCRUZ, Center of Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation on Neglected Diseases Population (INCT-IDPN), Rio de Janeiro 21040-900, Brazil; (G.C.L.); (P.N.-P.); (L.R.G.); (D.W.P.J.)
| | - David William Provance
- FIOCRUZ, Center of Technological Development in Health (CDTS), National Institute of Science and Technology for Innovation on Neglected Diseases Population (INCT-IDPN), Rio de Janeiro 21040-900, Brazil; (G.C.L.); (P.N.-P.); (L.R.G.); (D.W.P.J.)
- Interdisciplinary Medical Research Laboratory, Oswaldo Cruz Institute/FIOCRUZ, Rio de Janeiro 21040-900, Brazil;
| | - Vinícius Dias Nirello
- Faculty of Pharmacy, Federal of Rio de Janeiro University, Rio de Janeiro 21949-900, Brazil; (V.D.N.); (A.C.R.S.)
| | - Ana Carolina Rennó Sodero
- Faculty of Pharmacy, Federal of Rio de Janeiro University, Rio de Janeiro 21949-900, Brazil; (V.D.N.); (A.C.R.S.)
| | - Herbert Leonel de Mattos Guedes
- Interdisciplinary Medical Research Laboratory, Oswaldo Cruz Institute/FIOCRUZ, Rio de Janeiro 21040-900, Brazil;
- Laboratory of Immunopharmacology, Federal of Rio de Janeiro University, Duque de Caxias 25245-390, Brazil
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Pérez-Escalante E, Cruz-Guerrero AE, Álvarez-Romero GA, Mendoza-Huizar LH, Flores-Aguilar JF, González-Olivares LG. Urea as the best fibrin solubilizer in the thrombin inhibition analysis: Theoretical and experimental modeling of fibrinogen denaturation. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Bañares-Hidalgo Á, Pérez-Gil J, Estrada P. Conformational Stability of the NH2-Terminal Propeptide of the Precursor of Pulmonary Surfactant Protein SP-B. PLoS One 2016; 11:e0158430. [PMID: 27380171 PMCID: PMC4933373 DOI: 10.1371/journal.pone.0158430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/15/2016] [Indexed: 11/18/2022] Open
Abstract
Assembly of pulmonary surfactant lipid-protein complexes depends on conformational changes coupled with proteolytic maturation of proSP-B, the precursor of pulmonary surfactant protein B (SP-B), along the surfactant biogenesis pathway in pneumocytes. Conformational destabilization of the N-terminal propeptide of proSP-B (SP-BN) triggers exposure of the mature SP-B domain for insertion into surfactant lipids. We have studied the conformational stability during GdmCl- or urea-promoted unfolding of SP-BN with trp fluorescence and circular dichroism spectroscopies. Binding of the intermediate states to bis-ANS suggests their molten globule-like character. ΔG0H2O was ~ 12.7 kJ·mol-1 either with urea or GdmCl. None of the thermal transitions of SP-BN detected by CD correspond to protein unfolding. Differential scanning calorimetry of SP-BN evidenced two endothermic peaks involved in oligomer dissociation as confirmed with 2 M urea. Ionic strength was relevant since at 150 mM NaCl, the process originating the endotherm at the highest temperature was irreversible (Tm2 = 108.5°C) with an activation energy of 703.8 kJ·mol-1. At 500 mM NaCl the process became reversible (Tm2 = 114.4°C) and data were fitted to the Non-two States model with two subpeaks. No free thiols in the propeptide could be titrated by DTNB with or without 5.7 M GdmCl, indicating disulfide bonds establishment.
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Affiliation(s)
- Ángeles Bañares-Hidalgo
- Departamento de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, Ciudad Universitaria, 28040, Madrid, Spain
| | - Jesús Pérez-Gil
- Departamento de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, Ciudad Universitaria, 28040, Madrid, Spain
- * E-mail:
| | - Pilar Estrada
- Departamento de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, Ciudad Universitaria, 28040, Madrid, Spain
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Esquembre R, Sanz JM, Wall JG, del Monte F, Mateo CR, Ferrer ML. Thermal unfolding and refolding of lysozyme in deep eutectic solvents and their aqueous dilutions. Phys Chem Chem Phys 2013; 15:11248-56. [DOI: 10.1039/c3cp44299c] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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5
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Allosteric activation of human α-thrombin through exosite 2 by suramin analogs. Arch Biochem Biophys 2012; 520:36-41. [DOI: 10.1016/j.abb.2012.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/22/2022]
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Silva VDA, Cargnelutti MT, Giesel GM, Palmieri LC, Monteiro RQ, Verli H, Lima LMTR. Structure and behavior of human α-thrombin upon ligand recognition: thermodynamic and molecular dynamics studies. PLoS One 2011; 6:e24735. [PMID: 21935446 PMCID: PMC3173475 DOI: 10.1371/journal.pone.0024735] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 08/16/2011] [Indexed: 11/19/2022] Open
Abstract
Thrombin is a serine proteinase that plays a fundamental role in coagulation. In this study, we address the effects of ligand site recognition by alpha-thrombin on conformation and energetics in solution. Active site occupation induces large changes in secondary structure content in thrombin as shown by circular dichroism. Thrombin-D-Phe-Pro-Arg-chloromethyl ketone (PPACK) exhibits enhanced equilibrium and kinetic stability compared to free thrombin, whose difference is rooted in the unfolding step. Small-angle X-ray scattering (SAXS) measurements in solution reveal an overall similarity in the molecular envelope of thrombin and thrombin-PPACK, which differs from the crystal structure of thrombin. Molecular dynamics simulations performed with thrombin lead to different conformations than the one observed in the crystal structure. These data shed light on the diversity of thrombin conformers not previously observed in crystal structures with distinguished catalytic and conformational behaviors, which might have direct implications on novel strategies to design direct thrombin inhibitors.
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Affiliation(s)
- Vivian de Almeira Silva
- School of Pharmacy, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Federal Institute of Rio de Janeiro for Science and Technology Education, Rio de Janeiro, Brazil
- Medical Biochemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Maria Thereza Cargnelutti
- School of Pharmacy, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
- Medical Biochemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Guilherme M. Giesel
- School of Pharmacy, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
- Center for Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Leonardo C. Palmieri
- School of Pharmacy, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Robson Q. Monteiro
- Medical Biochemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Hugo Verli
- School of Pharmacy, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
- Center for Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Kumar A, Gaikwad SM. Multistate unfolding of α-mannosidase from Canavalia ensiformis (Jack Bean): Evidence for the thermostable molten globule. Biochem Biophys Res Commun 2010; 403:391-7. [DOI: 10.1016/j.bbrc.2010.11.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 11/12/2010] [Indexed: 11/28/2022]
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de C. Palmieri L, Lima LMTR, Freire JBB, Bleicher L, Polikarpov I, Almeida FCL, Foguel D. Novel Zn2+-binding sites in human transthyretin: implications for amyloidogenesis and retinol-binding protein recognition. J Biol Chem 2010; 285:31731-41. [PMID: 20659897 PMCID: PMC2951245 DOI: 10.1074/jbc.m110.157206] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Indexed: 11/06/2022] Open
Abstract
Human transthyretin (TTR) is a homotetrameric protein involved in several amyloidoses. Zn(2+) enhances TTR aggregation in vitro, and is a component of ex vivo TTR amyloid fibrils. We report the first crystal structure of human TTR in complex with Zn(2+) at pH 4.6-7.5. All four structures reveal three tetra-coordinated Zn(2+)-binding sites (ZBS 1-3) per monomer, plus a fourth site (ZBS 4) involving amino acid residues from a symmetry-related tetramer that is not visible in solution by NMR. Zn(2+) binding perturbs loop E-α-helix-loop F, the region involved in holo-retinol-binding protein (holo-RBP) recognition, mainly at acidic pH; TTR affinity for holo-RBP decreases ∼5-fold in the presence of Zn(2+). Interestingly, this same region is disrupted in the crystal structure of the amyloidogenic intermediate of TTR formed at acidic pH in the absence of Zn(2+). HNCO and HNCA experiments performed in solution at pH 7.5 revealed that upon Zn(2+) binding, although the α-helix persists, there are perturbations in the resonances of the residues that flank this region, suggesting an increase in structural flexibility. While stability of the monomer of TTR decreases in the presence of Zn(2+), which is consistent with the tertiary structural perturbation provoked by Zn(2+) binding, tetramer stability is only marginally affected by Zn(2+). These data highlight structural and functional roles of Zn(2+) in TTR-related amyloidoses, as well as in holo-RBP recognition and vitamin A homeostasis.
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Affiliation(s)
| | | | | | - Lucas Bleicher
- the Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo 13560-970, Brazil
| | - Igor Polikarpov
- the Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo 13560-970, Brazil
| | - Fabio C. L. Almeida
- From the Instituto de Bioquimica Medica, Programa de Biologia Estrutural
- Centro Nacional de Ressonância Magnética Nuclear de Macromoléculas Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil and
| | - Debora Foguel
- From the Instituto de Bioquimica Medica, Programa de Biologia Estrutural
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López G, Bañares-Hidalgo A, Estrada P. Xylanase II from Trichoderma reesei QM 9414: conformational and catalytic stability to Chaotropes, Trifluoroethanol, and pH changes. J Ind Microbiol Biotechnol 2010; 38:113-25. [DOI: 10.1007/s10295-010-0836-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/26/2010] [Indexed: 11/24/2022]
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10
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Bañares-Hidalgo A, Bolaños-Gutiérrez A, Gil F, Cabré EJ, Pérez-Gil J, Estrada P. Self-aggregation of a recombinant form of the propeptide NH2-terminal of the precursor of pulmonary surfactant protein SP-B: a conformational study. J Ind Microbiol Biotechnol 2008; 35:1367-76. [PMID: 18797948 DOI: 10.1007/s10295-008-0437-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 07/30/2008] [Indexed: 12/23/2022]
Abstract
A recombinant form of the peptide N-terminally positioned from proSP-B (SP-BN) has been produced in Escherichia coli as fusion with the Maltose Binding Protein, separated from it by Factor Xa cleavage and purified thereafter. This protein module is thought to control assembly of mature SP-B, a protein essential for respiration, in pulmonary surfactant as it progress through the progressively acidified secretory pathway of pneumocytes. Self-aggregation studies of the recombinant propeptide have been carried out as the pH of the medium evolved from neutral to moderately acid, again to neutral and finally basic. The profile of aggregation versus subsequent changes in pH showed differences depending on the ionic strength of the medium, low or moderate, and the presence of additives such as L-arginine (a known aggregation suppressor) and Ficoll 70 (a macromolecular crowder). Circular dichroism studies of SP-BN samples along the aggregation process showed a decrease in alpha-helical content and a concomitant increase in beta-sheet. Intrinsic fluorescence emission of SP-BN was dominated by the emission of Trp residues in neutral medium, being its emission maximum shifted to red at low pH, suggesting that the protein undergoes a pH-dependent conformational change that increases the exposure of their Trp to the environment. A marked increase in the fluorescence emission of the extrinsic probe bis-ANS indicated the exposure of hydrophobic regions of SP-BN at pH 5. The fluorescence of bis-ANS decreased slightly at low ionic strength, but to a great extent at moderate ionic strength when the pH was reversed to neutrality, suggesting that self-aggregation properties of the SP-BN module could be tightly modulated by the conditions of pH and the ionic environment encountered by pulmonary surfactant during assembly and secretion.
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Affiliation(s)
- A Bañares-Hidalgo
- Departamento de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, Ciudad Universitaria, 28040, Madrid, Spain
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Guedes HLM, Silva FP, Netto CC, de Salles CMC, Alexandre G, Oliveira CLP, Torriani I, De Simone SG. Structural characterization and low-resolution model of BJ-48, a thrombin-like enzyme from Bothrops jararacussu venom. Biophys Chem 2007; 132:159-64. [PMID: 18069115 DOI: 10.1016/j.bpc.2007.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 11/08/2007] [Accepted: 11/08/2007] [Indexed: 11/16/2022]
Abstract
Thrombin-like enzymes (TLEs) are important components of snake venoms due to their involvement in coagulopathies occurring on envenoming. Structural characterization of this group of serine proteases is of utmost importance for better understanding their unique properties. However, the high carbohydrate content of some members of this group prevents successful crystallization for structural determination. Circumventing this difficulty, the structure of BJ-48, a highly glycosylated TLE from Bothrops jararacussu venom, was studied in solution. At pH 8.0, where the enzyme displays maximum activity, BJ-48 has a radius of gyration (Rg) of 37 A and a maximum dimension (D(max)) of 130 A as measured by small-angle X-ray scattering (SAXS) and a Stokes radius (SR) of 50 A according to dynamic light scattering (DLS) data. At the naturally more acidic pH (6.0) of the B. jararacussu venom BJ-48 behaves as a more compact particle as evidenced by SAXS (R(g)=27.9 A and D(max)=82 A) and DLS (SR=30 A) data. In addition, Kratky plot analysis indicates a rigid shape at pH 8.0 and a flexible shape at pH 6.0. On the other hand, the center of mass of intrinsic fluorescence was not changed while varying pH, possibly indicating the absence of fluorescent amino acids in the regions affected by pH variation. Circular dichroism experiments carried out with BJ-48 indicate a substantially random coiled secondary structure that is not affected by pH. Low-resolution model of BJ-48 presented a prolate elongated shape at pH 8.0 and a U-shape at 6.0. BJ-48 tertiary structure at pH 6.0 was maintained on heating up to 52 degrees C and was completely lost at 75 degrees C. The possible existence of two pH-induced folding states for BJ-48 and its importance for the biological role and stability of this enzyme was discussed.
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Affiliation(s)
- Herbert L M Guedes
- Laboratório de Bioquímica de Proteínas e Peptídeos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, RJ, Brazil
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(NZ)CH...O contacts assist crystallization of a ParB-like nuclease. BMC STRUCTURAL BIOLOGY 2007; 7:46. [PMID: 17617922 PMCID: PMC1940005 DOI: 10.1186/1472-6807-7-46] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Accepted: 07/07/2007] [Indexed: 11/13/2022]
Abstract
Background The major bottleneck for determination of 3 D structures of proteins using X-rays is the production of diffraction quality crystals. Often proteins are subjected to chemical modification to improve the chances of crystallization Results Here, we report the successful crystallization of a nuclease employing a reductive methylation protocol. The key to crystallization was the successful introduction of 44 new cohesive (NZ) CH...O contacts (3.2 – 3.7 Å) by the addition of 2 methyl groups to the side chain amine nitrogen (NZ) of 9 lysine residues of the nuclease. The new contacts dramatically altered the crystallization properties of the protein, resulting in crystals that diffracted to 1.2 Å resolution. Analytical ultracentrifugation analysis and thermodynamics results revealed a more compact protein structure with better solvent exclusion of buried Trp residues in the folded state of the methylated protein, assisting crystallization. Conclusion In this study, introduction of novel cohesive (NZ)CH...O contacts by reductive methylation resulted in the crystallization of a protein that had previously resisted crystallization in spite of extensive purification and crystallization space screening. Introduction of (NZ)CH...O contacts could provide a solution to crystallization problems for a broad range of protein targets.
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Polizzotti BD, Kiick KL. Effects of polymer structure on the inhibition of cholera toxin by linear polypeptide-based glycopolymers. Biomacromolecules 2006; 7:483-90. [PMID: 16471920 PMCID: PMC2657727 DOI: 10.1021/bm050672n] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A variety of important biological events are mediated by the multivalent interaction between relevant oligosaccharides and multiple saccharide receptors on lectins, toxins, and cell surfaces; a variety of glycopolymeric materials have therefore been investigated in studies aimed at manipulating these events. The synthesis of protein- and polypeptide-based glycopolymers via protein engineering and other methods offers opportunities to control both the number and the spacing of saccharides on a scaffold, as well as the conformation of the polymer backbone, and will therefore facilitate the structure-based design of polymers for inhibition of multivalent binding events. In initial studies, we have synthesized a family of galactose-functionalized glycopolymers with a poly(L-glutamic acid) backbone, in which the density and linker length of the pendant carbohydrate moiety were varied. The composition of the glycopolymers was determined via (1)H NMR spectroscopy, and the impact of saccharide density and linker length, as well as the potential for these polypeptide-based glycopolymers to act as high-affinity inhibitors of the cholera toxin, has been indicated via competitive enzyme-linked immunosorbent assay and fluorescence titration experiments. The results of these studies suggest strategies for optimizing the binding of linear glycopolymers to bacterial toxins and will aid in the design of additional protein-based materials for studying the impact of multivalency, spacing, and backbone rigidity in a variety of biologically relevant binding events.
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Fujimoto Y, Ikeuchi H, Tada T, Oyama H, Oda K, Kunugi S. Synergetic effects of pressure and chemical denaturant on protein unfolding: stability of a serine-type carboxyl protease, kumamolisin. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1764:364-71. [PMID: 16478682 DOI: 10.1016/j.bbapap.2005.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 12/10/2005] [Accepted: 12/13/2005] [Indexed: 11/25/2022]
Abstract
Kumamolisin, a serine carboxyl proteinase, is very stable and hardly denatured by single perturbation of a chemical denaturant (urea), pressure (<500 MPa) or temperature (<65 degrees C). In order to investigate the cooperative effects of these three denaturing agents, DSC, CD, intrinsic fluorescence, and fourth derivative UV absorbance were measured under various conditions. By application of pressure to kumamolisin in 8 M urea solution, substantial red-shift in the center of fluorescence emission spectral mass was observed, and the corresponding blue-shift was observed for two major peaks in fourth derivative UV absorbance, under the similar urea-containing conditions. The denaturation curves were analyzed on the basis of a simple two-state model in order to obtain thermodynamic parameters (DeltaV, DeltaG, and m values), and the combined effects of denaturing agents are discussed, with the special interest in the large cavity and neighboring Trp residue in kumamolisin.
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Affiliation(s)
- Yasunori Fujimoto
- Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo, 606-8585, Japan
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