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Awada H, Grison CM, Charnay-Pouget F, Baltaze JP, Brisset F, Guillot R, Robin S, Hachem A, Jaber N, Naoufal D, Yazbeck O, Aitken DJ. Conformational Effects through Hydrogen Bonding in a Constrained γ-Peptide Template: From Intraresidue Seven-Membered Rings to a Gel-Forming Sheet Structure. J Org Chem 2017; 82:4819-4828. [PMID: 28398045 DOI: 10.1021/acs.joc.7b00494] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A series of three short oligomers (di-, tri-, and tetramers) of cis-2-(aminomethyl)cyclobutane carboxylic acid, a γ-amino acid featuring a cyclobutane ring constraint, were prepared, and their conformational behavior was examined spectroscopically and by molecular modeling. In dilute solutions, these peptides showed a number of low-energy conformers, including ribbonlike structures pleated around a rarely observed series of intramolecular seven-membered hydrogen bonds. In more concentrated solutions, these interactions defer to an organized supramolecular assembly, leading to thermoreversible organogel formation notably for the tripeptide, which produced fibrillar xerogels. In the solid state, the dipeptide adopted a fully extended conformation featuring a one-dimensional network of intermolecularly H-bonded molecules stacked in an antiparallel sheet alignment. This work provides unique insight into the interplay between inter- and intramolecular H-bonded conformer topologies for the same peptide template.
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Affiliation(s)
- Hawraà Awada
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France.,Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon
| | - Claire M Grison
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
| | - Florence Charnay-Pouget
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
| | - Jean-Pierre Baltaze
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
| | - François Brisset
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
| | - Régis Guillot
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
| | - Sylvie Robin
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France.,UFR Sciences Pharmaceutiques et Biologiques, Université Paris Descartes , 4 avenue de l'Observatoire, 75270 Paris cedex 06, France
| | - Ali Hachem
- Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon
| | - Nada Jaber
- Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon
| | - Daoud Naoufal
- Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon
| | - Ogaritte Yazbeck
- Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon
| | - David J Aitken
- CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France
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López-Martínez C, Flores-Morales P, Cruz M, González T, Feliz M, Diez A, Campanera JM. Proline cis-trans isomerization and its implications for the dimerization of analogues of cyclopeptide stylostatin 1: a combined computational and experimental study. Phys Chem Chem Phys 2016; 18:12755-67. [PMID: 27097793 DOI: 10.1039/c5cp05937b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cis and trans proline conformers are often associated with dramatic changes in the biological function of peptides. A slow equilibrium between cis and trans Ile-Pro amide bond conformers occurs in constrained derivatives of the native marine cyclic heptapeptide stylostatin 1 (cyclo-(NSLAIPF)), a potential anticancer agent. In this work, four cyclopeptides, cyclo-(NSTAIPF), cyclo-(KSTAIPF), cyclo-(RSTAIPF) and cyclo-(DSTAIPF), which are structurally related to stylostatin 1, are experimentally and computationally examined in order to assess the effect of residue mutations on the cis-trans conformational ratio and the apparent capacity to form dimeric aggregates. Primarily, cyclo-(KSTAIPF) and cyclo-(RSTAIPF) showed specific trends in circular dichroism, MALDI-TOF and HPLC purification experiments, which suggests the occurrence of peptide dimerization. Meanwhile, the NMR spectrum of cyclo-(KSTAIPF) indicates that this cyclopeptide exists in the two slow-exchange families of conformations mentioned above. Molecular dynamics simulations combined with quantum mechanical calculations have shed light on the factors governing the cis/trans conformational ratio. In particular, we have found that residue mutations affect the internal hydrogen bond pattern which ultimately tunes the cis/trans conformational ratio and that only trans conformers are capable of aggregating due to the shape complementarity of the two subunits.
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Affiliation(s)
- C López-Martínez
- Laboratori de Química Orgànica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, Universitat de Barcelona, 08028 Barcelona, Spain
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