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Amiri A, Abedanzadeh S, Davaeil B, Shaabani A, Moosavi-Movahedi AA. Protein click chemistry and its potential for medical applications. Q Rev Biophys 2024; 57:e6. [PMID: 38619322 DOI: 10.1017/s0033583524000027] [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] [Indexed: 04/16/2024]
Abstract
A revolution in chemical biology occurred with the introduction of click chemistry. Click chemistry plays an important role in protein chemistry modifications, providing specific, sensitive, rapid, and easy-to-handle methods. Under physiological conditions, click chemistry often overlaps with bioorthogonal chemistry, defined as reactions that occur rapidly and selectively without interfering with biological processes. Click chemistry is used for the posttranslational modification of proteins based on covalent bond formations. With the contribution of click reactions, selective modification of proteins would be developed, representing an alternative to other technologies in preparing new proteins or enzymes for studying specific protein functions in different biological processes. Click-modified proteins have potential in diverse applications such as imaging, labeling, sensing, drug design, and enzyme technology. Due to the promising role of proteins in disease diagnosis and therapy, this review aims to highlight the growing applications of click strategies in protein chemistry over the last two decades, with a special emphasis on medicinal applications.
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Affiliation(s)
- Ahmad Amiri
- Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | | | - Bagher Davaeil
- Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Ahmad Shaabani
- Department of Chemistry, Shahid Beheshti University, Tehran, Iran
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2
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Gajula SNR, Nadimpalli N, Sonti R. Drug metabolic stability in early drug discovery to develop potential lead compounds. Drug Metab Rev 2021; 53:459-477. [PMID: 34406889 DOI: 10.1080/03602532.2021.1970178] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Knowledge of the metabolic stability of a new drug substance eliminated by biotransformation is essential for envisaging the pharmacokinetic parameters required for deciding drug dosing and frequency. Strategies aimed at modifying lead compounds may improve metabolic stability, thereby reducing the drug dosing frequency. Replacement of selective hydrogens with deuterium can effectively enhance the drug's metabolic stability by increasing the biological half-life. Further, cyclization, change in ring size, and chirality can substantially improve the metabolic stability of drugs. The microsomal t1/2 approach for measuring drug in vitro intrinsic clearance by automated LC-MS/MS offers sensitive high-throughput screens with reliable data. The obtained in vitro intrinsic clearance from metabolic stability data helps predict the drug's in vivo total clearance using different scaling factors and hepatic clearance models. This review summarizes all the recent approaches and technological advancements in metabolic stability studies for narrowing down the potential lead compounds in drug discovery. Further, we summarized the potential pitfalls and assumptions made during the in vivo intrinsic clearance estimation from in vitro intrinsic clearance.
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Affiliation(s)
- Siva Nageswara Rao Gajula
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Nimisha Nadimpalli
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Rajesh Sonti
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
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3
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Ahangarpour M, Kavianinia I, Harris PWR, Brimble MA. Photo-induced radical thiol-ene chemistry: a versatile toolbox for peptide-based drug design. Chem Soc Rev 2021; 50:898-944. [PMID: 33404559 DOI: 10.1039/d0cs00354a] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
While the global market for peptide/protein-based therapeutics is witnessing significant growth, the development of peptide drugs remains challenging due to their low oral bioavailability, poor membrane permeability, and reduced metabolic stability. However, a toolbox of chemical approaches has been explored for peptide modification to overcome these obstacles. In recent years, there has been a revival of interest in photoinduced radical thiol-ene chemistry as a powerful tool for the construction of therapeutic peptides.
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Affiliation(s)
- Marzieh Ahangarpour
- School of Chemical Sciences, The University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
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4
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Liu H, Gao L, Yu X, Zhong L, Shi J, Jia B, Li N, Liu Z, Wang F. Small-animal SPECT/CT imaging of cancer xenografts and pulmonary fibrosis using a 99mTc-labeled integrin αvβ6-targeting cyclic peptide with improved in vivo stability. BIOPHYSICS REPORTS 2018; 4:254-264. [PMID: 30533490 PMCID: PMC6245143 DOI: 10.1007/s41048-018-0071-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 07/17/2018] [Indexed: 12/20/2022] Open
Abstract
Abstract Integrin αvβ6 is expressed at an undetectable level in normal tissues, but is remarkably upregulated during many pathological processes, especially in cancer and fibrosis. Noninvasive imaging of integrin αvβ6 expression using a radiotracer with favorable in vivo pharmacokinetics would facilitate disease diagnosis and therapy monitoring. Through disulfide-cyclized method, we synthesized in this study, a new integrin αvβ6-targeted cyclic peptide (denoted as cHK), and radiolabeled it with 99mTc. The ability of the resulting radiotracer 99mTc–HYNIC–cHK to detect integrin αvβ6 expression in pancreatic cancer xenografts and idiopathic pulmonary fibrosis was evaluated using small-animal single-photon emission computed tomography (SPECT)/computed tomography (CT). 99mTc–HYNIC–cHK showed significantly improved in vivo metabolic stability compared to the linear peptide-based radiotracer 99mTc–HYNIC–HK. 99mTc–HYNIC–cHK exhibited similar biodistribution properties to 99mTc–HYNIC–HK, but the tumor-to-muscle ratio was significantly increased (2.99 ± 0.87 vs. 1.82 ± 0.27, P < 0.05). High-contrast images of integrin αvβ6-positive tumors and bleomycin-induced fibrotic lungs were obtained by SPECT/CT imaging using 99mTc–HYNIC–cHK. Overall, our studies demonstrate that 99mTc–HYNIC–cHK is a promising SPECT radiotracer for the noninvasive imaging of integrin αvβ6 in living subjects. Graphical Abstract ![]()
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Affiliation(s)
- Hao Liu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Liquan Gao
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Xinhe Yu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Lijun Zhong
- Medical and Healthy Analytical Center, Peking University, Beijing, 100191 China
| | - Jiyun Shi
- Key Laboratory of Protein and Peptide Pharmaceuticals, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
| | - Bing Jia
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
- Medical and Healthy Analytical Center, Peking University, Beijing, 100191 China
| | - Nan Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Nuclear Medicine, Peking University Cancer Hospital & Institute, Beijing, 100142 China
| | - Zhaofei Liu
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
| | - Fan Wang
- Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191 China
- Key Laboratory of Protein and Peptide Pharmaceuticals, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 China
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5
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Reher R, Kühl T, Annala S, Benkel T, Kaufmann D, Nubbemeyer B, Odhiambo JP, Heimer P, Bäuml CA, Kehraus S, Crüsemann M, Kostenis E, Tietze D, König GM, Imhof D. Deciphering Specificity Determinants for FR900359-Derived Gqα Inhibitors Based on Computational and Structure-Activity Studies. ChemMedChem 2018; 13:1634-1643. [DOI: 10.1002/cmdc.201800304] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Indexed: 01/14/2023]
Affiliation(s)
- Raphael Reher
- Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Toni Kühl
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
| | - Suvi Annala
- Molecular, Cellular and Pharmacobiology Section; Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Tobias Benkel
- Molecular, Cellular and Pharmacobiology Section; Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Desireé Kaufmann
- Eduard Zintl Institute for Inorganic and Physical Chemistry; Technische Universität Darmstadt; Alarich-Weiss-Str. 4 64287 Darmstadt Germany
| | - Britta Nubbemeyer
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
| | - Justin Patrick Odhiambo
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
| | - Pascal Heimer
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
| | - Charlotte Anneke Bäuml
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
| | - Stefan Kehraus
- Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Max Crüsemann
- Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Evi Kostenis
- Molecular, Cellular and Pharmacobiology Section; Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Daniel Tietze
- Eduard Zintl Institute for Inorganic and Physical Chemistry; Technische Universität Darmstadt; Alarich-Weiss-Str. 4 64287 Darmstadt Germany
| | - Gabriele M. König
- Institute of Pharmaceutical Biology; University of Bonn; Nussallee 6 53115 Bonn Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics; Pharmaceutical Institute; University of Bonn; An der Immenburg 4 53121 Bonn Germany
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6
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Flexible or fixed: a comparative review of linear and cyclic cancer-targeting peptides. Future Med Chem 2012; 4:1601-18. [PMID: 22917248 DOI: 10.4155/fmc.12.75] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Peptides can serve as versatile cancer-targeting ligands and have been used for clinically relevant applications such as cancer imaging and therapy. A current and long-standing focus within peptide research is the creation of structurally constrained peptides generated through cyclization. Cyclization is envisioned to enhance the selective binding, uptake, potency and stability of linear precursors. This review compares closely related linear and cyclic peptides in these respects. Peptide cyclization generally improves the selective binding and stability of linear precursors; however, not all cyclization strategies and constrained geometries enhance these properties to the same extent. In some instances, linear analogues actually have better cancer-targeting properties compared with their cyclic counterparts. Although cyclization does not necessarily improve the cancer-targeting properties of linear analogues, cyclic peptides may obtain properties that allow them to be used for additional applications. This review aims to convey the advantages and limitations of cyclic cancer-targeting peptides.
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Martí-Centelles V, Burguete MI, Luis SV. Template Effects in SN2 Displacements for the Preparation of Pseudopeptidic Macrocycles. Chemistry 2012; 18:2409-22. [DOI: 10.1002/chem.201101416] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 09/20/2011] [Indexed: 11/07/2022]
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8
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Zoda MS, Zacharias M, Reissmann S. Syntheses and activities of backbone-side chain cyclic octapeptide ligands with N
-functionalized phosphotyrosine for the N
-terminal SH2-domain of the protein tyrosine phosphatase SHP-1. J Pept Sci 2010; 16:403-13. [DOI: 10.1002/psc.1256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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9
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Ovadia O, Greenberg S, Laufer B, Gilon C, Hoffman A, Kessler H. Improvement of drug-like properties of peptides: the somatostatin paradigm. Expert Opin Drug Discov 2010; 5:655-71. [DOI: 10.1517/17460441.2010.493935] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Aimetti AA, Shoemaker RK, Lin CC, Anseth KS. On-resin peptide macrocyclization using thiol-ene click chemistry. Chem Commun (Camb) 2010; 46:4061-3. [PMID: 20379591 DOI: 10.1039/c001375g] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A versatile and rapid synthetic strategy has been developed for the on-resin cyclization of peptides using thiol-ene photochemistry. This unique method exploits the thiol group of natural cysteine amino acids and allows for various alkenes to be incorporated orthogonal to the peptide backbone.
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Affiliation(s)
- Alex A Aimetti
- Department of Chemical & Biological Engineering, University of Colorado, Boulder, CO 80309, USA
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11
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Ngyen H, Orlamuender M, Pretzel D, Agricola I, Sternberg U, Reissmann S. Transition metal complexes of a cyclic pseudo hexapeptide: synthesis, complex formation and catalytic activities. J Pept Sci 2008; 14:1010-21. [DOI: 10.1002/psc.1037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Comparative Study of Chemical Approaches to the Solid-Phase Synthesis of a Tumor-Seeking α-MSH Analogue. Int J Pept Res Ther 2008. [DOI: 10.1007/s10989-008-9143-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Vaz B, Brunsveld L. Stable helical peptoids via covalent side chain to side chain cyclization. Org Biomol Chem 2008; 6:2988-94. [PMID: 18688493 DOI: 10.1039/b806847j] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peptoids are oligomeric N-substituted glycines with potential as biologically relevant compounds. Helical peptoids provide an attractive fold for the generation of protein-protein interaction inhibitors. The generation of helical peptoid folds in organic and aqueous media has been limited to strict design rules, as peptoid-folding is mainly directed via the steric direction of alpha-chiral side-chains. Here a new methodology is presented to induce helical folds in peptoids with the aid of side chain to side chain cyclization. Cyclic peptoids were generated via solid-phase synthesis and their folding was studied. The cyclization induces significant helicity in peptoids in organic media, aids the folding in aqueous media, and requires the incorporation of only relatively few chiral aromatic side chains.
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Affiliation(s)
- Belén Vaz
- Max Planck Institute of Molecular Physiology, and Chemical Genomics Centre, D-44227, Dortmund, Germany
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14
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Gomes P, Vale N, Moreira R. Cyclization-activated prodrugs. Molecules 2007; 12:2484-506. [PMID: 18065953 PMCID: PMC6149143 DOI: 10.3390/12112484] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 11/08/2007] [Accepted: 11/09/2007] [Indexed: 11/16/2022] Open
Abstract
Many drugs suffer from an extensive first-pass metabolism leading to drug inactivation and/or production of toxic metabolites, which makes them attractive targets for prodrug design. The classical prodrug approach, which involves enzyme-sensitive covalent linkage between the parent drug and a carrier moiety, is a well established strategy to overcome bioavailability/toxicity issues. However, the development of prodrugs that can regenerate the parent drug through non-enzymatic pathways has emerged as an alternative approach in which prodrug activation is not influenced by inter- and intraindividual variability that affects enzymatic activity. Cyclization-activated prodrugs have been capturing the attention of medicinal chemists since the middle-1980s, and reached maturity in prodrug design in the late 1990 s. Many different strategies have been exploited in recent years concerning the development of intramoleculary-activated prodrugs spanning from analgesics to anti-HIV therapeutic agents. Intramolecular pathways have also a key role in two-step prodrug activation, where an initial enzymatic cleavage step is followed by a cyclization-elimination reaction that releases the active drug. This work is a brief overview of research on cyclization-activated prodrugs from the last two decades.
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Affiliation(s)
- Paula Gomes
- Centro de Investigação em Química da Universidade do Porto, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Porto, Portugal.
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15
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Brust A, Tickle AE. High-throughput synthesis of conopeptides: a safety-catch linker approach enabling disulfide formation in 96-well format. J Pept Sci 2007; 13:133-41. [PMID: 17160973 DOI: 10.1002/psc.825] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Conotoxins exhibit a high degree of selectivity and potency for a range of pharmacologically relevant targets. The rapid access to libraries of conotoxin analogues, containing multiple intramolecular disulfide bridges for use in drug development, can be a very labor intensive, multi-step task. This work describes a high-throughput method for the synthesis of cystine-bridged conopeptides. Peptides were assembled on a peptide synthesizer employing the Fmoc solid-phase strategy using a safety-catch amide linker (SCAL). Side-chain protecting groups were removed on solid phase before SCAL activation with ammonium iodide in TFA, finally releasing the peptide into the TFA solution. Disulfide bond formation was performed in the cleavage mixture employing DMSO. This improved method allows mixtures of oxidized peptides to be obtained in parallel directly from a peptide synthesizer. A single HPLC purification of the resulting crude oxidized material produced peptides of > 95% purity.
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Affiliation(s)
- Andreas Brust
- Xenome Ltd, 120 Meiers Road, Indooroopilly 4068, Australia.
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Imhof D, Nothmann D, Zoda MS, Hampel K, Wegert J, Böhmer FD, Reissmann S. Synthesis of linear and cyclic phosphopeptides as ligands for theN-terminal SH2-domain of protein tyrosine phosphatase SHP-1. J Pept Sci 2005; 11:390-400. [PMID: 15635669 DOI: 10.1002/psc.631] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Linear and cyclic phosphopeptides related to the pY2267 binding site of the epithelial receptor tyrosine kinase Ros have been synthesized as ligands for the amino-terminal SH2 (src homology) domain of protein tyrosine phosphatase SHP-1. The synthesis was accomplished by Fmoc-based solid-phase methodology using side-chain unprotected phosphotyrosine for the linear and mono-benzyl protected phosphotyrosine for the cyclic peptides. According to molecular modelling, the incorporation of a glycine residue between Lys (position pY-1 relative to phosphotyrosine) and Asp or Glu (position pY+2) was recommended for the cyclic candidates. The preparation of these peptides was successfully performed by the incorporation of a Fmoc-Xxx(Gly-OAll)-OH (Xxx = Asp, Glu) dipeptide building block that was prepared in solution prior to SPPS. The cyclization was achieved with PyBOP following Alloc/OAll-deprotection. This study demonstrates the usefulness of allyl-type protecting groups for the generation of side-chain cyclized phosphopeptides. Alloc/OAll-deprotection and cyclization are compatible with phosphorylated tyrosine.
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Affiliation(s)
- Diana Imhof
- Institute of Biochemistry and Biophysics, Biological-Pharmaceutical Faculty, Friedrich-Schiller-University, Philosophenweg 12, D-07743 Jena, Germany.
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Nguyen HH, Imhof D, Kronen M, Schlegel B, Härtl A, Gräfe U, Gera L, Reissmann S. Synthesis and biological evaluation of analogues of the peptaibol ampullosporin A. J Med Chem 2002; 45:2781-7. [PMID: 12061880 DOI: 10.1021/jm0208018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of analogues of the fungal peptaibol type metabolite ampullosporin A containing modifications in the C and N terminus as well as alpha-aminoisobutyric acid (Aib) substitutions in different positions of the peptide were synthesized by solid phase synthesis using the 9-fluorenylmethyloxycarbonyl strategy. Depending on the sequence position, couplings were performed with 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/1-hydroxybenzotriazole and tetramethylfluoroformamidinium hexafluorophosphate, respectively. The structures of the target peptides were analyzed by electrospray ionization mass spectrometry and chromatographic methods (high-performance liquid chromatography, thin-layer chromatography). The biological activities of these compounds have been evaluated by assaying their potencies for the induction of pigment formation on the fungus Phoma destructiva as well as for the induction of hypothermia and inhibition of locomotoric activity in mice and were compared to the naturally occurring ampullosporins. Native ampullosporin A and analogues with C-terminal Leu or Leu-NH(2) showed comparable activity in the pigmentation assay. Similarly, the ampullosporin A analogues with N-terminal aromatic amino acid residues, such as D-Trp and Tic, also have high potency for pigment formation. The peptides containing structural modifications of ampullosporin A by systematic replacement of Aib by Ala (Ala scan) displayed moderate or high activity in the pigmentation assay, whereas simultaneous substitution of all Aib residues by Ala and Ile, respectively, or by insertion of nonaromatic residues into position 1 resulted in a loss of the effect on P. destructiva. Most of the compounds with no or weak activity in the microbial assay were not active in the hypothermic test, too, except the compound with 1-amino-1-cyclohexane carboxylic acid in position 4 instead of Aib. However, only a few compounds with high potency for pigmentation induction were found to produce strong hypothermia in mice. Thus, in contrast to the native ampullosporins, we succeeded to a certain degree in differentiation of the bioactivities with our synthetic analogues.
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Affiliation(s)
- Hoai-Huong Nguyen
- Institut für Biochemie und Biophysik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, D-07743 Jena, Germany
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