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Nikravesh FY, Gholami P, Bayat E, Talebkhan Y, Mirabzadeh E, Damough S, Aliabadi HAM, Nematollahi L, Ardakani YH. Expression, Purification, and Biological Evaluation of XTEN-GCSF in a Neutropenic Rat Model. Appl Biochem Biotechnol 2024; 196:804-820. [PMID: 37209276 DOI: 10.1007/s12010-023-04522-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2023] [Indexed: 05/22/2023]
Abstract
Granulocyte colony-stimulating factor (GCSF) stimulates the proliferation of neutrophils but it has low serum half-life. Therefore, the present study was done to investigate the effect of XTENylation on biological activity, pharmacokinetics, and pharmacodynamics of GCSF in a neutropenic rat model. XTEN tag was genetically fused to the N-terminal region of GCSF-encoding gene fragment and subcloned into pET28a expression vector. The cytoplasmic expressed recombinant protein was characterized through intrinsic fluorescence spectroscopy (IFS), dynamic light scattering (DLS), and size exclusion chromatography (SEC). In vitro biological activity of the XTEN-GCSF protein was evaluated on NFS60 cell line. Hematopoietic properties and pharmacokinetics were also investigated in a neutropenic rat model. An approximately 140 kDa recombinant protein was detected on SDS-PAGE. Dynamic light scattering and size exclusion chromatography confirmed the increase in hydrodynamic diameter of GCSF molecule after XTENylation. GCSF derivatives showed efficacy in proliferation of NFS60 cell line among which the XTEN-GCSF represented the lowest EC50 value (100.6 pg/ml). Pharmacokinetic studies on neutropenic rats revealed that XTEN polymer could significantly increase protein serum half-life in comparison with the commercially available GCSF molecules. PEGylated and XTENylated GCSF proteins were more effective in stimulation of neutrophils compared to the GCSF molecule alone. XTENylation of GCSF represented promising results in in vitro and in vivo studies. This approach can be a potential alternative to PEGylation strategies for increasing serum half-life of protein.
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Affiliation(s)
| | - Parisa Gholami
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Elham Bayat
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Yeganeh Talebkhan
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
| | - Esmat Mirabzadeh
- Department of Molecular Medicine, Pasteur Institute of Iran, Tehran, Iran
| | - Shadi Damough
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | | | - Leila Nematollahi
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Smith DK. From fundamental supramolecular chemistry to self-assembled nanomaterials and medicines and back again – how Sam inspired SAMul. Chem Commun (Camb) 2018; 54:4743-4760. [DOI: 10.1039/c8cc01753k] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Personal inspiration led to the development of a programme of research targeting the use of self-assembled systems in nanomedicine, which in the process of approaching a range of applications has uncovered new fundamental concepts in supramolecular science.
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Gstrein C, Zhang B, Abdel-Rahman MA, Bertran O, Alemán C, Wegner G, Schlüter AD. Solvatochromism of dye-labeled dendronized polymers of generation numbers 1-4: comparison to dendrimers. Chem Sci 2016; 7:4644-4652. [PMID: 30155112 PMCID: PMC6013770 DOI: 10.1039/c5sc04609b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/06/2016] [Indexed: 11/23/2022] Open
Abstract
Two series of dendronized polymers (DPs) of generations g = 1-4 with different levels of dendritic substitution (low and high) and a solvatochromic probe at g = 1 level are used to study their swelling behavior in a collection of solvents largely differing in polarity as indicated by the Kamlet-Taft parameters. This is done by measuring the UV-Vis spectra of all samples in all solvents and determining the longest wavelength absorptions (λmax). The λmax values fall into a range defined by the extreme situations, when the solvatochromic probe is either fully surrounded by solvent or completely shielded against it. The former situation is achieved in a model compound and the latter situation is believed to be reached when in a poor solvent the dendritic shell around the backbone is fully collapsed. We observe that solvent penetration into the interior of the DPs decreases with increasing g and does so faster for the more highly dendritically substituted series than for the less highly substituted one. Interestingly, the swelling of the more highly substituted DP series already at the g = 4 level has decreased to approximately 20% of that at the g = 1 level which supports an earlier proposal that high g DPs can be viewed as nano-sized molecular objects. Furthermore, when comparing these two DP series with a g = 1-6 series of dendrimers investigated by Fréchet et al. it becomes evident that even the less substituted series of DPs is much less responsive to solvent changes as assessed by the solvatochromic probe than the dendrimers, suggesting the branches around the (polymeric) core in DPs to be more densely packed compared to those in dendrimers, thus, establishing a key difference between these two dendritic macromolecules.
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Affiliation(s)
- Chiara Gstrein
- Laboratory of Polymer Chemistry , Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 5 , 8093 Zürich , Switzerland .
| | - Baozhong Zhang
- Centre of Analysis and Synthesis , Lund University , P.O. Box 124 , SE-22100 Lund , Sweden .
| | | | - Oscar Bertran
- Departament de Física Aplicada , EEI , Universitat Politècnica de Catalunya , Av. Pla de la Massa, 8 , 08700 Igualada , Spain
| | - Carlos Alemán
- Departament de Física Aplicada , EEI , Universitat Politècnica de Catalunya , Av. Pla de la Massa, 8 , 08700 Igualada , Spain
- Departament d'Enginyeria Quimica , E. T. S. d'Enginyeria Industrial de Barcelona , Universitat Politechnica de Catalunya , Diagonal 647 , Barcelona , E-08028 , Spain
- Center for Research in Nano-Engineering , Universitat Politècnica de Catalunya , Campus Sud, Edifici C', C/Pasqual i Vila s/n , Barcelona E-08028 , Spain
| | - Gerhard Wegner
- Max-Planck-Institute for Polymer Research , Ackermannweg 10 , 55128 Mainz , Germany
| | - A Dieter Schlüter
- Laboratory of Polymer Chemistry , Department of Materials , ETH Zurich , Vladimir-Prelog-Weg 5 , 8093 Zürich , Switzerland .
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Ghosh R, Mukherjee M, Chattopadhyay K, Ghosh S. Unusual Optical Resolution of All Four Tryptophan Residues in MPT63 Protein by Phosphorescence Spectroscopy: Assignment and Significance. J Phys Chem B 2012; 116:12489-500. [DOI: 10.1021/jp307526f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ranendu Ghosh
- Structural Biology & Bio-Informatics Division, Indian Institute of Chemical Biology, Kolkata-700 032, India
| | - Manini Mukherjee
- Department of Chemistry, Presidency University, Kolkata 700 073, India
| | - Krishnananda Chattopadhyay
- Structural Biology & Bio-Informatics Division, Indian Institute of Chemical Biology, Kolkata-700 032, India
| | - Sanjib Ghosh
- Department of Chemistry, Presidency University, Kolkata 700 073, India
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Affiliation(s)
- George R. Newkome
- Departments of Polymer Science and Chemistry, University of Akron, Akron, Ohio 44325-4717, and Department of Chemistry, Hiram College, Hiram, Ohio 44234
| | - Carol Shreiner
- Departments of Polymer Science and Chemistry, University of Akron, Akron, Ohio 44325-4717, and Department of Chemistry, Hiram College, Hiram, Ohio 44234
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6
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Alivertis D, Paraskevopoulos G, Theodorou V, Skobridis K. Dendritic effects of crown ether-functionalized dendrimers on the solvent extraction of metal ions. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.08.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Pavan GM, Danani A, Pricl S, Smith DK. Modeling the Multivalent Recognition between Dendritic Molecules and DNA: Understanding How Ligand “Sacrifice” and Screening Can Enhance Binding. J Am Chem Soc 2009; 131:9686-94. [DOI: 10.1021/ja901174k] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Giovanni M. Pavan
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Andrea Danani
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - Sabrina Pricl
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
| | - David K. Smith
- Molecular Simulations Engineering (MOSE) Laboratory, Department of Chemical Engineering (DICAMP), University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy, Institute of Computer Integrated Manufacturing for Sustainable Innovation (ICIMSI), University for Applied Sciences of Southern Switzerland (SUPSI), Centro Galleria 2, Manno, CH-6928, Switzerland, and Department of Chemistry, University of York, Heslington, York, YO10 5DD, U.K
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8
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Pedras B, Oliveira E, Santos H, Rodríguez L, Crehuet R, Avilés T, Capelo JL, Lodeiro C. A new tripodal poly-imine indole-containing ligand: Synthesis, complexation, spectroscopic and theoretical studies. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.11.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Wang BB, Li WS, Jia XR, Gao M, Jiang L, Wei Y. Photophysical and self-assembly behavior of poly(amidoamine) dendrons with chromophore as scaffold: The effect of dendritic architecture. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/pola.22802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Calderon M, Monzón LMA, Martinelli M, Juarez AV, Strumia MC, Yudi LM. Electrochemical study of a dendritic family at the water/1,2-dichloroethane interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6343-6350. [PMID: 18491871 DOI: 10.1021/la704052b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The transfer of six dendritric molecules, DMs, across the water/1,2-dichloroethane interface was investigated using cyclic voltammetry. From the variation of peak potential with pH, two different mechanisms of transfer were postulated depending on the nature of the molecules. Voltammetric parameters were employed to evaluate the hydrophilic/hydrophobic character and calculate the acid dissociation constant of these molecules. The results were explained taking into account the nature and multiplicity of functional surface groups.
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Affiliation(s)
- Marcelo Calderon
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IMBIV, Córdoba 5000, Argentina
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11
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Barriau E, Pastor-Pérez L, Berger-Nicoletti E, Kilbinger AFM, Frey H, Stiriba SE. Systematic investigation of functional core variation within hyperbranched polyglycerols. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/pola.22539] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Friebolin W, Jannack B, Wenzel N, Furrer J, Oeser T, Sanchez CP, Lanzer M, Yardley V, Becker K, Davioud-Charvet E. Antimalarial Dual Drugs Based on Potent Inhibitors of Glutathione Reductase from Plasmodium falciparum. J Med Chem 2008; 51:1260-77. [DOI: 10.1021/jm7009292] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wolfgang Friebolin
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Beate Jannack
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Nicole Wenzel
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Julien Furrer
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Thomas Oeser
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Cecilia P. Sanchez
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Michael Lanzer
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Vanessa Yardley
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Katja Becker
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
| | - Elisabeth Davioud-Charvet
- Biochemie-Zentrum der Universität Heidelberg, Im Neuenheimer Feld 504, 69120 Heidelberg, Germany, Organisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany, Hygiene Institut, Abt. Parasitologie, Im Neuenheimer Feld 324, 69120 Heidelberg, Department of Infections and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, U.K., Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32,
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Sardar PS, Maity SS, Das L, Ghosh S. Luminescence studies of perturbation of tryptophan residues of tubulin in the complexes of tubulin with colchicine and colchicine analogues. Biochemistry 2007; 46:14544-56. [PMID: 18041823 DOI: 10.1021/bi701412k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tubulin, a heterodimeric (alphabeta) protein, the main constituent of microtubules, binds efficiently with colchicine (consisting of a trimethoxybenzene ring, a seven-member ring and methoxy tropone moiety) and its analogues, viz., demecolcine and AC [2-methoxy-5-(2',3',4'-trimethoxyphenyl)tropone]. Tubulin contains eight tryptophan (Trp) residues at A21, A346, A388, A407, B21, B103, B346, and B407 in the two subunits. The role of these eight Trp residues in this interaction and also their perturbation due to binding have been explored via time-resolved fluorescence at room temperature and low-temperature (77 K) phosphorescence in a suitable cryosolvent. Both the time-resolved fluorescence data and 77 K phosphorescence spectra indicate that the emitting residues move toward a more hydrophobic and less polar environment after complex formation. The environment of emitting Trps in the complex also becomes slightly more heterogeneous. Our analysis using the experimental results, the calculation of the accessible surface area (ASA) of all the Trps in the wild type and tubulin-colchicine complex [Ravelli, R. B. G., et al. (2004) Nature 428, 198-202], the distance of the Trp residues from the different moieties of the colchicine molecule, the knowledge of the nature of the immediate residues (<5 A) present near each Trp residue, and the calculation of the intramolecular Trp-Trp energy transfer efficiencies indicate that Trp A346, Trp A407, Trp B21, and Trp B407 are the major contributors to the emission in the free protein, while Trp B21 and Trp B103 are mainly responsible for the emission of the complexes. A comparative account of the photophysical aspects of the drug molecules bound to protein in aqueous buffer and in buffer containing 40% ethylene glycol has been presented. The quantum yield and average lifetime of fluorescence in tubulin and its complexes with colchicine are used to predict the possible donors and the energy transfer (ET) efficiency in the ET process from Trps to colchicine in the complex. This study is a unique attempt to identify the Trp residues contributing to the emission in the free protein and in a complex of a multi-Trp protein with a drug molecule without performing the mutation of the protein.
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Ohrn A, Karlström G. Simulations of the Absorption and Fluorescence of Indole in Aqueous Solution and at a Nonpolar/Polar Interface. J Phys Chem A 2007; 111:10468-77. [PMID: 17914774 DOI: 10.1021/jp0744477] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Theoretical results are presented on the absorption and fluorescence of indole in aqueous solution as well as at the air/water surface. We use a combined quantum chemical statistical mechanical model with explicit solvent. An approximate ab initio complete active space self-consistent field description of the indole molecule is used, coupled to a discrete polarizable water medium. From the bulk simulations, strong support is found for the interchange mechanism, which explains the unusual solvent shift of the fluorescence of indole or tryptophan in a polar surrounding by a solvent induced switch of the fluorescing state. Two mechanisms are given to explain the different shifts for indole at the interface. First, a dielectric depletion effect, which is expected from the reduction of the amount of polar media. Second, an interface-specific effect, which derives from the stronger hydrogen bond formation at the surface. The latter effect acts to increase the shift for both absorption and emission at the surface as compared to the bulk. From these results, the intrinsic probe photophysics of tryptophan in proteins is discussed in terms of the properties of the protein/solvent interface and the orientation of the amino acid.
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Affiliation(s)
- Anders Ohrn
- Department of Theoretical Chemistry, Chemical Center, P.O. Box 124, S-221 00 Lund, Sweden.
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15
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Coates IA, Hirst AR, Smith DK. Optimizing Biomimetic Gelators Constructed from Amino Acid Building Blocks. J Org Chem 2007; 72:3937-40. [PMID: 17439286 DOI: 10.1021/jo070317i] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper reports the use of a range of amino acids to construct diverse gelators, employing structures in which Boc-protected amino acids are attached to either end of an aliphatic diamine spacer chain. The choice of amino acid determines whether nanoscale self-assembly takes place and controls the properties of the resultant material, while the function of the amino acid (e.g., the optical properties of tryptophan) is translated into the self-assembled nanostructured gel.
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Affiliation(s)
- Ian A Coates
- Department of Chemistry, University of York, Heslington, York YO10 5DD, UK
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Harvey BJ, Bell E, Brancaleon L. A Tryptophan Rotamer Located in a Polar Environment Probes pH-Dependent Conformational Changes in Bovine β-Lactoglobulin A. J Phys Chem B 2007; 111:2610-20. [PMID: 17300189 DOI: 10.1021/jp065783a] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bovine beta-lactoglobulin A (BLGA) is a well characterized globular protein whose tertiary structure has been investigated in detail. BLGA undergoes a pH-dependent conformational change which X-ray data described as involving mostly the loop connecting strands E and F and the deprotonation of a glutamic acid residue (Glu89). These structural changes have been investigated using, among other techniques, fluorescence spectroscopy. The intrinsic fluorescence of BLGA is dominated by two Trp residues. These residues are located far from the EF loop and would not be expected to probe the pH-induced conformational change of the protein. Trp19 is located at the bottom of the interior beta-barrel, whereas Trp61 is located at the aperture of the barrel near the CD loop and is "silent" in the emission of native BLGA because of the proximity of a disulfide moiety. Our study suggests that, surprisingly, the fluorescence of Trp19 has the characteristic of a more polar environment than structural models from X-ray data would suggest and that at least two distinct conformations (or rotamers) of Trp19 contribute to the fluorescence of the protein. The less populated rotamer (relative amplitude (alpha) approximately 20%, tau approximately 3 ns) probes a more polar environment and a pH-dependent conformational change of BLGA in the region of Trp19 which X-ray data do not detect. Finally, our study provides the estimate of the fluorescence lifetime of Trp61 in the "unquenched" form.
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Affiliation(s)
- Billie J Harvey
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas, USA
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Hardy JG, Ashworth I, Brennan C, Smith DK. Dendritic receptors designed to bind polyanions in both organic and aqueous media. Org Biomol Chem 2007; 5:900-6. [PMID: 17340005 DOI: 10.1039/b618063a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper reports the synthesis of dendrons containing a spermine unit at their focal point. The dendritic branching is based on l-lysine building blocks, and has terminal oligo(ethyleneglycol) units on the surface. As a consequence of the solubilising surface groups, these dendrons have high solubility in solvents with widely different polarities (e.g., dichloromethane and water). The protonated spermine unit at the focal point is an effective anion binding fragment and, as such, these dendrons are able to bind to polyanions. This paper demonstrates that polyanions can be bound in both dichloromethane (using a dye solubilisation assay) and in water (competitive ATP binding assay). In organic media the dendritic branching appears to have a pro-active effect on the solubilisation of the dye, with more dye being solubilised by higher generations of dendron. On the other hand, in water the degree of branching has no impact on the anion binding process. We propose that in this case, the spermine unit is effectively solvated by the bulk solvent and the dendritic branching does not need to play an active role in assisting solubility. Dendritic effects on anion binding have therefore been elucidated in different solvents. The dendritic branching plays a pro-active role in providing the anion binding unit with good solubility in apolar solvent media.
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Affiliation(s)
- John G Hardy
- Department of Chemistry, University of York, York, UK YO10 5DD
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Domracheva N, Mirea A, Schwoerer M, Torre-Lorente L, Lattermann G. Magnetic Properties of Poly(propylene imine)-Copper Dendromesogenic Complexes: An EPR Study. Chemphyschem 2006; 7:2567-77. [PMID: 17089431 DOI: 10.1002/cphc.200600360] [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] [Indexed: 11/06/2022]
Abstract
Copper(II) complexes formed by coordination of the Cu(II) ion with liquid-crystalline poly(propylene imine) dendrimer ligand (L) of the first (complex 1) and second (complex 2) generations with various Cu(II) contents (x = Cu/L) have been studied by electron paramagnetic resonance (EPR) spectroscopy. The existence of a redox-active blue complex 1 (x = 1.9) and the copper(II) nitrate electron transfer associated with the valence tautomerism are revealed for the first time in copper-based dendrimers. It has been shown that the electronic structure of the blue complex 1 (x = 1.9) is adequately described as a mixed-valence dimer containing d9- and diamagnetic d10-configurated copper ions, and an antiferromagnetically coupled NO3* radical arising on the nitrate-bridged counter ligand. The activation energy value found for the electron transfer is about 0.35 meV, which indicates a low-energy charge dynamic. The ability of the blue and green complexes 1 (x = 1.9) dissolved in isotropic solvents to orient themselves in the magnetic field was revealed by EPR spectroscopy. The degree of orientation of the molecular z axis (S(z)) of these complexes in the magnetic field differs, depending on the type of copper(II)-complexing site in the dendrimer ligand, and can reach 0.76, which is close to S(z) = 1 (completely aligned system). A combination of magnetic and orientational parameters indicates an NO4 environment of the Cu(II) ion in green complex 1 (x = 1.9), and confirms the chain structure with intermolecular Cu(II)-NO3-Cu(II) bridges between Cu(II) centres in columns.
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Affiliation(s)
- Natalia Domracheva
- Zavoisky Kazan Physical-Technical Institute, Russian Academy of Science, 420029 Kazan, Russia.
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Love CS, Ashworth I, Brennan C, Chechik V, Smith DK. Dendron-protected Au nanoparticles—Effect of dendritic structure on chemical stability. J Colloid Interface Sci 2006; 302:178-86. [PMID: 16808922 DOI: 10.1016/j.jcis.2006.05.064] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 04/28/2006] [Accepted: 05/30/2006] [Indexed: 11/19/2022]
Abstract
A series of gold nanoparticles stabilised by 'Newkome-type' dendritic branching has been synthesised and fully characterised. In particular, the properties and behaviour of these hybrid materials are compared with those of a previously reported set of nanoparticles stabilised by dendrons constructed using l-lysine building blocks. The rates of cyanide-induced nanoparticle decomposition were determined, and it was found that the rate of decomposition increased on the introduction of dendritic branching. Furthermore, 'Newkome-type' dendrons were significantly more effective at protecting the encapsulated gold nanoparticle than the l-lysine based dendrons. It is proposed that this observation can be explained on the basis of more effective packing and surface coverage by the 'Newkome-type' dendrons. Importantly, this study therefore demonstrates that the organic chemical structure of dendritic ligands plays a crucial role in controlling the reactivity of self-assembled hybrid nanostructures.
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Affiliation(s)
- Christine S Love
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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Mohanty SK, Baskaran S, Mishra AK. Bathochromic shift of the fluorescence spectral maximum with increasing generation of dansyl labeled Newkome type dendrimers. Eur Polym J 2006. [DOI: 10.1016/j.eurpolymj.2006.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Portugal CAM, Crespo JG, Lima JC. Anomalous “unquenching” of the fluorescence decay times of β-lactoglobulin induced by the known quencher acrylamide. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2006; 82:117-26. [PMID: 16288883 DOI: 10.1016/j.jphotobiol.2005.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 08/22/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
Picosecond time-resolved fluorescence, together with the addition of quenching agents, was employed to discriminate the fluorescence contributions of the two tryptophans of beta-lactoglobulin (Trp19 and Trp61) to the fluorescence decays of the protein. The fluorescence decays of beta-lactoglobulin at pH 3, 5 and 8 are best fitted using sums of three exponentials and show a dominant contribution (98%) of the components associated with the buried Trp19, which decays according to a double exponential function. The addition of acrylamide (0.05 M) causes an increase of the decay times associated with Trp19. This effect is observed at all pH values studied, but the effect is stronger at pH 3 and pH 5, than at pH 8. The unexpected increase of the decay times of Trp19 and the variation of the respective amplitudes were rationalized in terms of alterations of Trp19 mobility. The hindrance of Trp19 upon acrylamide binding was also monitored and supported by fluorescence anisotropy measurements.
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Affiliation(s)
- Carla A M Portugal
- Requimte-CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, Monte da Caparica, 2825-516 Caparica, Portugal
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Smith DK, Hirst AR, Love CS, Hardy JG, Brignell SV, Huang B. Self-assembly using dendritic building blocks—towards controllable nanomaterials. Prog Polym Sci 2005. [DOI: 10.1016/j.progpolymsci.2005.01.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Stone DL, Smith DK, Whitwood AC. Copper amino-acid complexes – towards encapsulated metal centres. Polyhedron 2004. [DOI: 10.1016/j.poly.2004.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Dykes GM, Smith DK. Supramolecular dendrimer chemistry: using dendritic crown ethers to reversibly generate functional assemblies. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00468-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Chasse TL, Yohannan JC, Kim N, Li Q, Li Z, Gorman CB. Dendritic encapsulation-roles of cores and branches. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00435-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Stone DL, Dykes GM, Smith DK. Dendritic lanthanide complexes and the effect of Lewis-acid encapsulation. Dalton Trans 2003. [DOI: 10.1039/b309643b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Cardona CM, Gawley RE. An improved synthesis of a trifurcated newkome-type monomer and orthogonally protected two-generation dendrons. J Org Chem 2002; 67:1411-3. [PMID: 11846699 DOI: 10.1021/jo0161678] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The one-step synthesis of amino-polyether tri-tert-butyl ester monomer 2, by condensation of TRIS with tert-butyl acrylate, is reported. The nitrogen of the monomer can be protected with a Cbz group; subsequent removal of the tert-butyl esters with formic acid affords a triacid that is coupled to three monomers to afford an orthogonally protected two-generation, trifurcated polyether-polyamide dendron. The Cbz protecting group may be removed from the second-generation dendron without disturbing the tert-butyl esters of the periphery.
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Affiliation(s)
- Claudia M Cardona
- Department of Chemistry and NIEHS Marine and Freshwater Biomedical Sciences Center, University of Miami, P.O. Box 249118, Coral Gables, Florida 33124-0431, USA
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Stone DL, Smith DK, McGrail PT. Ferrocene encapsulated within symmetric dendrimers: a deeper understanding of dendritic effects on redox potential. J Am Chem Soc 2002; 124:856-64. [PMID: 11817961 DOI: 10.1021/ja0117478] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ferrocene has been encapsulated within a symmetric ether-amide dendritic shell and its redox potential monitored in a variety of solvents. The dendritic effect generated by the branched shell is different in different solvents. In less polar, non hydrogen bond donor solvents, attachment of the branched shell to ferrocene increases its E(1/2), indicating that oxidation to ferrocenium (charge buildup) becomes thermodynamically hindered by the dendrimer, a result explained by the dendrimer providing a less polar medium than that of the surrounding electrolyte solution. The effect of electrolyte concentration on redox potential was also investigated, and it was shown that the concentration of "innocent" electrolyte has a significant effect on the redox potential by increasing the overall polarity of the surrounding medium. Dendritic destabilization of charge buildup is in agreement with the majority of reported dendritic effects. A notable exception to this is provided by the asymmetric ferrocene dendrimers previously reported by Kaifer and co-workers, in which the branching facilitated oxidation, and it is proposed that in this case the dendritic effect is generated by a different mechanism. Interestingly, in methanol, the new symmetric ferrocene dendrimer exhibited almost no dendritic effect, a result explained by the ability of methanol to interact extensively with the branched shell, generating a more open superstructure. By comparison of all the new data with other reports, this study provides a key insight into the structure-activity relationships which control redox processes in dendrimers and also an insight into the electrochemical process itself.
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Affiliation(s)
- Diane L Stone
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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Dykes GM, Brierley LJ, Smith DK, McGrail PT, Seeley GJ. Supramolecular solubilisation of hydrophilic dyes by using individual dendritic branches. Chemistry 2001; 7:4730-9. [PMID: 11757666 DOI: 10.1002/1521-3765(20011105)7:21<4730::aid-chem4730>3.0.co;2-a] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Individual dendritic branches can solubilise hydrophilic dyes in apolar media. The functional group at the focal point of the dendritic branch plays a key role in the dye uptake process. Supramolecular interactions between carboxylic acid and amine groups have been shown to be effective in enabling efficient solubilisation to occur. The necessary complementarity of this interaction is further illustrated by a series of control experiments. The extent of dendritic branching (i.e. dendritic generation) plays a key role in controlling the extent of dye uptake, with higher-generation dendritic branches exhibiting more efficient uptake at lower concentrations. UV/Visible spectroscopic methods have shown that the dendritic branches, in addition to the tuning of the extent of dye uptake, also tune the optical properties of the solubilised dye and this provides further insight into the interactions occurring between the solubilised dye and the individual dendritic branches. Furthermore, it is shown that suitably functionalised dendritic branches can transport hydrophilic dyes through an apolar phase and deliver them continuously into an aqueous medium.
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Affiliation(s)
- G M Dykes
- Department of Chemistry, University of York Heslington, UK.
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Davis AV, Driffield M, Smith DK. A dendritic active site: catalysis of the Henry reaction. Org Lett 2001; 3:3075-8. [PMID: 11573998 DOI: 10.1021/ol016197x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from L-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performance was compared with that of triethylamine. Attachment of the dendritic shell alters the rate of reaction and influences the syn:anti ratio of products. It is proposed that the dendritic shell generates an encapsulated catalytically active site, mimicking the behavior of a protein superstructure.
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Affiliation(s)
- A V Davis
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK
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Beinhoff M, Weigel W, Jurczok M, Rettig W, Modrakowski C, Brüdgam I, Hartl H, Schlüter A. Synthesis and Spectroscopic Properties of Arene-Substituted Pyrene Derivatives as Model Compounds for Fluorescent Polarity Probes. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200110)2001:20<3819::aid-ejoc3819>3.0.co;2-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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