Synthesis and biological evaluation of new inhibitors of HIV-1 protease dimerization and \u3b1V\u3b23-integrin atagonists with pptidomimetic Structures.

Despite the versatile and interesting function of peptides in biological systems, metabolic instability and poor bioavailability make them ineffective as orally administered drugs. Due to these limitations, peptidomimetic compounds are preferred as drug candidates. This thesis deals with the design and the synthesis of peptidomimetics. In the Chapter I, peptidomimetics were introduced in molecular tongs as dimerization inhibitors of wild-type and mutated HIV-1 Proteases. HIV-1 protease (PR) is a homodimer of two identical 99-amino acid subunits in which the active site is generated by self-assembly of these subunits. Remarkably, the antiparallel fsheet formed by interdigitation of N- and C-terminal strands of each protease monomer, which contributes over 75 % to the stabilizing force of the dimer, is found relatively free of mutations. By targeting this highly conserved dimerization interface, we demonstrated that HIV-1 protease dimer is disrupted with loss of activity by constrained molecular tongs based on naphthalene scaffold. We describe here the synthesis, the enzyme inhibitory activity against wild-type and mutated HIV-1 PR, of new molecular tongs containing amino acid mimetic fragments in one or two strands. In the Chapter II, diketopiperazine scaffold was introduced in cyclic RGD peptidomimetics, as new integrin inhibitors. Synthetic peptides and peptidomimetics, containing the arginine-glycine-aspartate (RGD) motif, have been widely used as inhibitors of integrin-ligand interactions to study cell growth, adhesion, migration and differentiation. In many cases, the RGD sequence is combined with a secondary structure inducing element to form cyclic peptidomimetics. In this project, a few cyclic peptidomimetics containing a bifunctional diketopiperazine (DKP) unit (cis and trans) and the RGD sequence, were prepared by solution phase peptide synthesis, and tested as selective ligands for the integrins \u3b1v\u3b23 and \u3b1v\u3b2

Synthesis and biological evaluation of new inhibitors of HIV-1 protease dimerization and αVβ3-integrin atagonists with pptidomimetic Structures.

Despite the versatile and interesting function of peptides in biological systems, metabolic instability and poor bioavailability make them ineffective as orally administered drugs. Due to these limitations, peptidomimetic compounds are preferred as drug candidates. This thesis deals with the design and the synthesis of peptidomimetics. In the Chapter I, peptidomimetics were introduced in molecular tongs as dimerization inhibitors of wild-type and mutated HIV-1 Proteases. HIV-1 protease (PR) is a homodimer of two identical 99-amino acid subunits in which the active site is generated by self-assembly of these subunits. Remarkably, the antiparallel ßsheet formed by interdigitation of N- and C-terminal strands of each protease monomer, which contributes over 75 % to the stabilizing force of the dimer, is found relatively free of mutations. By targeting this highly conserved dimerization interface, we demonstrated that HIV-1 protease dimer is disrupted with loss of activity by constrained molecular tongs based on naphthalene scaffold. We describe here the synthesis, the enzyme inhibitory activity against wild-type and mutated HIV-1 PR, of new molecular tongs containing amino acid mimetic fragments in one or two strands. In the Chapter II, diketopiperazine scaffold was introduced in cyclic RGD peptidomimetics, as new integrin inhibitors. Synthetic peptides and peptidomimetics, containing the arginine-glycine-aspartate (RGD) motif, have been widely used as inhibitors of integrin-ligand interactions to study cell growth, adhesion, migration and differentiation. In many cases, the RGD sequence is combined with a secondary structure inducing element to form cyclic peptidomimetics. In this project, a few cyclic peptidomimetics containing a bifunctional diketopiperazine (DKP) unit (cis and trans) and the RGD sequence, were prepared by solution phase peptide synthesis, and tested as selective ligands for the integrins αvβ3 and αvβ

Synthèse et évaluation biologique de nouveaux inhibiteurs peptidomimétiques de la dimérisation de la protéase du VIH-1 et d antagonistes de avb3-intégrines

Dans le chapitre I, des peptidomimétiques ont été introduits dans des pinces moléculaires inhibitrices de la dimérisation de la Protéase de types sauvage et mutées du VIH-1. La protéase du VIH-1 (PR) est un homodimère constitué de deux sous-unités identiques de 99 acides aminés. Le feuillet b à 4 brins antiparallèles formé par les extrémités C- et N- terminales de chacun des monomères de la PR stabilise le dimère et est très conservé. En ciblant cette interface de dimérisation avec des pinces moléculaires, la protéase dimerique du VIH-1 est perturbée avec perte de l'activité. Nous décrivons ici la synthèse et l'activité inhibitrice contre la PR de types sauvage et mutées du VIH-1 de nouvelles pinces moléculaires contenant des fragments peptidomimétiques. Dans le chapitre II, des peptidomimétiques cycliques contenant une unité dicétopipérazine (cis et trans) et la séquence RGD, ont été préparés en phase liquide, et testés en tant que ligands sélectifs pour les intégrines avb3 et avb5.In the Chapter I, peptidomimetics were introduced in molecular tongs as dimerization inhibitors of wild-type and mutated HIV-1 Proteases. HIV-1 protease (PR) is a homodimer of two identical 99-amino acid subunits. The antiparallel ß-sheet formed by interdigitation of N- and C-terminal strands of each protease monomer contributes to the stabilizing force of the dimer and is highly conserved. By targeting this dimerization interface with constrained molecular tongs, HIV-1 protease dimer is disrupted with loss of activity. We describe here the synthesis, the enzyme inhibitory activity against wild-type and mutated HIV-1 PR, of new molecular tongs containing amino acid mimetic fragments. In the Chapter II, diketopiperazine scaffold was introduced in cyclic RGD peptidomimetics, as new integrin inhibitors. Cyclic peptidomimetics containing a bifunctional diketopiperazine unit (cis and trans) and the RGD sequence, were prepared and tested as selective ligands for the integrins avb3 and avb5.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Peptidomimetic dimerization inhibitors of HIV-1 protease : further insights into structural and mechanism of action.

International audienceMutations that occur in response to the HIV-1 protease inhibitors (PIs) are responsible for the development of multi-drug cross-resistance to PIs in AIDS treatment. Virtually all PIs act through the same mechanism: they are transition-state analogs that target the active site of the homodimeric enzyme located at the junction of the two monomers. The emergence of resistance to one PI usually results in cross-resistance to other PIs. One alternative to inhibiting the active site of HIV-1 protease is to target the dimer interface of the enzyme at the antiparallel beta-sheet formed by the interdigitation of the C- and N-ends of each monomer. This region is highly conserved and is responsible for about 75% of the dimer stabilization energy. Here we describe new dimerization inhibitors in which new structural molecular variations have been introduced and the peptidic characteristics have been decreased by introducing peptidomimetic groups that have peptide-like hydrogen bonding properties. This led to an increase of the in vitro efficiency (subnanomolar level) against HIV-1 protease activity. Our dimerization inhibitors proved equally active in vitro against both wild-type and mutated proteases. The mechanism of inhibition was established using a combination of kinetic and biophysical methods. Using analytical ultracentrifugation and NMR, we obtained direct experimental evidence of non-covalent dissociative mode of interaction of the HIV-1 protease dimerization inhibitor

Carbonylhydrazide-Based Molecular Tongs Inhibit Wild-Type and Mutated HIV-1 Protease Dimerization

International audienceWe have designed and synthesized new molecular tongs based on a rigid naphthalene scaffold and evaluated their antidimer activity on HIV-1 protease (PR). We inserted carbonylhydrazide and oligohydrazide (azatide) fragments into their peptidomimetic arms to reduce hydrophobicity and increase metabolic stability. These fragments are designed to disrupt the protein-protein interactions by reproducing the hydrogen bond pattern found in the antiparallel beta-sheet formed between the N- and C-ends of the two monomers in the native PR. Kinetic analyses and fluorescent probe binding studies showed that several molecular tongs can inhibit PR dimerization. The best nonpeptidic molecular tongs to date were obtained with an inhibition constant K-id of 50 nM for PR and 80 nM for the multimutated protease ANAM-11. The PR inhibition was selective, the aspartic proteases renin and pepsin were not inhibited

Carbonylhydrazide-Based Molecular Tongs Inhibit Wild-Type and Mutated HIV‑1 Protease Dimerization

We have designed and synthesized new molecular tongs based on a rigid naphthalene scaffold and evaluated their antidimer activity on HIV-1 protease (PR). We inserted carbonylhydrazide and oligohydrazide (azatide) fragments into their peptidomimetic arms to reduce hydrophobicity and increase metabolic stability. These fragments are designed to disrupt the protein–protein interactions by reproducing the hydrogen bond pattern found in the antiparallel β-sheet formed between the <i>N</i>- and <i>C</i>-ends of the two monomers in the native PR. Kinetic analyses and fluorescent probe binding studies showed that several molecular tongs can inhibit PR dimerization. The best nonpeptidic molecular tongs to date were obtained with an inhibition constant <i>K</i>_id of 50 nM for PR and 80 nM for the multimutated protease ANAM-11. The PR inhibition was selective, the aspartic proteases renin and pepsin were not inhibited