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Santi S, Biondi B, Cardena R, Bisello A, Schiesari R, Tomelleri S, Crisma M, Formaggio F. Helical versus Flat Bis-Ferrocenyl End-Capped Peptides: The Influence of the Molecular Skeleton on Redox Properties. Molecules 2022; 27:6128. [PMID: 36144860 PMCID: PMC9503075 DOI: 10.3390/molecules27186128] [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: 08/19/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 11/30/2022] Open
Abstract
Despite the fact that peptide conjugates with a pendant ferrocenyl (Fc) have been widely investigated, bis-ferrocenyl end-capped peptides are rarely synthetized. In this paper, in addition to the full characterization of the Fc-CO-[L-Dap(Boc)]n-NH-Fc series, we report a comparison of the three series of bis-ferrocenyl homopeptides synthesized to date, to gain insights into the influence of α-amino isobutyric (Aib), 2,3-diamino propionic (Dap) and Cα,β-didehydroalanine (ΔAla) amino acids on the peptide secondary structure and on the ferrocene redox properties. The results obtained by 2D NMR analysis and X-ray crystal structures, and further supported by electrochemical data, evidence different behaviors depending on the nature of the amino acid; that is, the formation of 310-helices or fully extended (2.05-helix) structures. In these foldamers, the orientation of the carbonyl groups in the peptide helix yields a macrodipole with the positive pole on the N-terminal amino acid and the negative pole on the C-terminal amino acid, so that oxidation of the Fc moieties takes place more or less easily depending on the orientation of the macrodipole moment as the peptide chain grows. Conversely, the fully extended conformation adopted by ΔAla flat peptides neither generates a macrodipole nor affects Fc oxidation. The utilization as electrochemical and optical (Circular Dichroism) probes of the two terminal Fc groups, bound to the same peptide chain, makes it possible to study the end-to-end effects of the positive charges produced by single and double oxidations, and to evidence the presence "exciton-coupled" CD among the two intramolecularly interacting Fc groups of the L-Dap(Boc) series.
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Affiliation(s)
- Saverio Santi
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Barbara Biondi
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Via Marzolo 1, 35131 Padova, Italy
| | - Roberta Cardena
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Annalisa Bisello
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Renato Schiesari
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Silvia Tomelleri
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Marco Crisma
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Via Marzolo 1, 35131 Padova, Italy
| | - Fernando Formaggio
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Via Marzolo 1, 35131 Padova, Italy
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Guryanov I, Korzhikov-Vlakh V, Bhattacharya M, Biondi B, Masiero G, Formaggio F, Tennikova T, Urtti A. Conformationally Constrained Peptides with High Affinity to the Vascular Endothelial Growth Factor. J Med Chem 2021; 64:10900-10907. [PMID: 34269584 DOI: 10.1021/acs.jmedchem.1c00219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The design of efficient vascular endothelial growth factor (VEGF) inhibitors is a high-priority research area aimed at the treatment of pathological angiogenesis. Among other compounds, v114* has been identified as a potent VEGF-binding peptide. In order to improve the affinity to VEGF, we built a conformational constrain in its structure. To this aim, Cα-tetrasubstituted amino acid Aib was introduced into the N-terminal tail, peptide loop, or C-terminal helix. NMR studies confirmed the stabilization of the helical conformation in proximity to the Aib residue. We found that the induction of the N-terminal helical structure or stabilization of the C-terminal helix can noticeably increase the peptide affinity to the VEGF. These peptides efficiently inhibited VEGF-stimulated cell proliferation as well. The insertion of the non-proteinogenic Aib residue significantly enhanced the stability of the peptides in the vitreous environment. Thus, these Aib-containing peptides are promising candidates for the design of VEGF inhibitors with improved properties.
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Affiliation(s)
- Ivan Guryanov
- Institute of Chemistry, St. Petersburg State University, Universitetsky pr. 26, Peterhof, St. Petersburg 198504, Russia
| | - Viktor Korzhikov-Vlakh
- Institute of Chemistry, St. Petersburg State University, Universitetsky pr. 26, Peterhof, St. Petersburg 198504, Russia
| | - Madhushree Bhattacharya
- Division of Pharmaceutical Biosciences, University of Helsinki, Viikinkaari 5 E, Helsinki 00014, Finland
| | - Barbara Biondi
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, via Marzolo 1, Padova 35131, Italy
| | - Giulia Masiero
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, via Marzolo 1, Padova 35131, Italy
| | - Fernando Formaggio
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, via Marzolo 1, Padova 35131, Italy
| | - Tatiana Tennikova
- Institute of Chemistry, St. Petersburg State University, Universitetsky pr. 26, Peterhof, St. Petersburg 198504, Russia
| | - Arto Urtti
- Division of Pharmaceutical Biosciences, University of Helsinki, Viikinkaari 5 E, Helsinki 00014, Finland.,School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, Kuopio 70211, Finland
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Solomon LA, Sykes ME, Wu YA, Schaller RD, Wiederrecht GP, Fry HC. Tailorable Exciton Transport in Doped Peptide-Amphiphile Assemblies. ACS NANO 2017; 11:9112-9118. [PMID: 28817256 DOI: 10.1021/acsnano.7b03867] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Light-harvesting biomaterials are an attractive target in photovoltaics, photocatalysis, and artificial photosynthesis. Through peptide self-assembly, complex nanostructures can be engineered to study the role of chromophore organization during light absorption and energy transport. To this end, we demonstrate the one-dimensional transport of excitons along naturally occurring, light-harvesting, Zn-protoporphyrin IX chromophores within self-assembled peptide-amphiphile nanofibers. The internal structure of the nanofibers induces packing of the porphyrins into linear chains. We find that this peptide assembly can enable long-range exciton diffusion, yet it also induces the formation of excimers between adjacent molecules, which serve as exciton traps. Electronic coupling between neighboring porphyrin molecules is confirmed by various spectroscopic methods. The exciton diffusion process is then probed through transient photoluminescence and absorption measurements and fit to a model for one-dimensional hopping. Because excimer formation impedes exciton hopping, increasing the interchromophore spacing allows for improved diffusivity, which we control through porphyrin doping levels. We show that diffusion lengths of over 60 nm are possible at low porphyrin doping, representing an order of magnitude improvement over the highest doping fractions.
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Affiliation(s)
- Lee A Solomon
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
| | - Matthew E Sykes
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
| | - Yimin A Wu
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Gary P Wiederrecht
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
| | - H Christopher Fry
- Center for Nanoscale Materials, Argonne National Laboratory , Lemont, Illinois 60439, United States
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Fry HC, Garcia JM, Medina MJ, Ricoy UM, Gosztola DJ, Nikiforov MP, Palmer LC, Stupp SI. Self-assembly of highly ordered peptide amphiphile metalloporphyrin arrays. J Am Chem Soc 2012; 134:14646-9. [PMID: 22916716 DOI: 10.1021/ja304674d] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Long fibers assembled from peptide amphiphiles capable of binding the metalloporphyrin zinc protoporphyrin IX ((PPIX)Zn) have been synthesized. Rational peptide design was employed to generate a peptide, c16-AHL(3)K(3)-CO(2)H, capable of forming a β-sheet structure that propagates into larger fibrous structures. A porphyrin-binding site, a single histidine, was engineered into the peptide sequence in order to bind (PPIX)Zn to provide photophysical functionality. The resulting system indicates control from the molecular level to the macromolecular level with a high order of porphyrin organization. UV/visible and circular dichroism spectroscopies were employed to detail molecular organization, whereas electron microscopy and atomic force microscopy aided in macromolecular characterization. Preliminary picosecond transient absorption data are also reported. Reduced hemin, (PPIX)Fe(II), was also employed to highlight the material's versatility and tunability.
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Affiliation(s)
- H Christopher Fry
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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Fry HC, Lehmann A, Saven JG, DeGrado WF, Therien MJ. Computational design and elaboration of a de novo heterotetrameric alpha-helical protein that selectively binds an emissive abiological (porphinato)zinc chromophore. J Am Chem Soc 2010; 132:3997-4005. [PMID: 20192195 PMCID: PMC2856663 DOI: 10.1021/ja907407m] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first example of a computationally de novo designed protein that binds an emissive abiological chromophore is presented, in which a sophisticated level of cofactor discrimination is pre-engineered. This heterotetrameric, C(2)-symmetric bundle, A(His):B(Thr), uniquely binds (5,15-di[(4-carboxymethyleneoxy)phenyl]porphinato)zinc [(DPP)Zn] via histidine coordination and complementary noncovalent interactions. The A(2)B(2) heterotetrameric protein reflects ligand-directed elements of both positive and negative design, including hydrogen bonds to second-shell ligands. Experimental support for the appropriate formulation of [(DPP)Zn:A(His):B(Thr)](2) is provided by UV/visible and circular dichroism spectroscopies, size exclusion chromatography, and analytical ultracentrifugation. Time-resolved transient absorption and fluorescence spectroscopic data reveal classic excited-state singlet and triplet PZn photophysics for the A(His):B(Thr):(DPP)Zn protein (k(fluorescence) = 4 x 10(8) s(-1); tau(triplet) = 5 ms). The A(2)B(2) apoprotein has immeasurably low binding affinities for related [porphinato]metal chromophores that include a (DPP)Fe(III) cofactor and the zinc metal ion hemin derivative [(PPIX)Zn], underscoring the exquisite active-site binding discrimination realized in this computationally designed protein. Importantly, elements of design in the A(His):B(Thr) protein ensure that interactions within the tetra-alpha-helical bundle are such that only the heterotetramer is stable in solution; corresponding homomeric bundles present unfavorable ligand-binding environments and thus preclude protein structural rearrangements that could lead to binding of (porphinato)iron cofactors.
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Affiliation(s)
- H. Christopher Fry
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
| | - Andreas Lehmann
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
| | - Jeffrey G. Saven
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
| | - William F. DeGrado
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323
- Department of Biochemistry and Molecular Biophysics, Johnson Foundation, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059
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