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Publikationen - Natur- und Wirkstoffchemie

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Publikation

Méndez, Y.; Vasco, A. V.; Ebensen, T.; Schulze, K.; Yousefi, M.; Davari, M. D.; Wessjohann, L. A.; Guzmán, C. A.; Rivera, D. G.; Westermann, B.; Diversification of a novel α‐galactosyl ceramide hotspot boosts the adjuvant properties in parenteral and mucosal vaccines Angew. Chem. Int. Ed. 63, e202310983, (2024) DOI: 10.1002/anie.202310983

The development of potent adjuvants is an important step for improving the performance of subunit vaccines. CD1d agonists, such as the prototypical α‐galactosyl ceramide (α‐GalCer), are of special interest due to their ability to activate iNKT cells and trigger rapid dendritic cell maturation and B‐cell activation. Herein, we introduce a novel derivatization hotspot at the α‐GalCer skeleton, namely the N‐substituent at the amide bond. The multicomponent diversification of this previously unexplored glycolipid chemotype space permitted the introduction of a variety of extra functionalities that can either potentiate the adjuvant properties or serve as handles for further conjugation to antigens toward the development of self‐adjuvanting vaccines. This strategy led to the discovery of compounds eliciting enhanced antigen‐specific T cell stimulation and a higher antibody response when delivered by either the parenteral or the mucosal route, as compared to a known potent CD1d agonist. Notably, various functionalized α‐GalCer analogues showed a more potent adjuvant effect after intranasal immunization than a PEGylated α‐GalCer analogue previously optimized for this purpose. Ultimately, this work could open multiple avenues of opportunity for the use of mucosal vaccines against microbial infections.
Publikation

Vasco, A. V.; Méndez, Y.; González, C.; Pérez, C. S.; Reguera, L.; Wessjohann, L. A.; Rivera, D. G.; Advancing multicomponent strategies to macrobicyclic peptides ChemBioChem 24, e202300229, (2023) DOI: 10.1002/cbic.202300229

Macrocyclization of peptides is typically used to fix specific bioactive conformations and improve their pharmacological properties. Recently, macrobicyclic peptides have received special attention owing to their capacity to mimic protein structures or be key components of peptide-drug conjugates. Here, we describe the development of novel synthetic strategies for two distinctive types of peptide macrobicycles. A multicomponent macrocyclo-dimerization approach is introduced for the production of interconnected β-turns, allowing two macrocyclic rings to be formed and dimerized in one pot. Also, an on-resin double stapling strategy is described for the assembly of lactam-bridged macrobicycles with stable tertiary folds.
Publikation

Humpierre, A. R.; Zanuy, A.; Saenz, M.; Vasco, A. V.; Méndez, Y.; Westermann, B.; Cardoso, F.; Quintero, L.; Santana, D.; Verez, V.; Valdés, Y.; Rivera, D. G.; Garrido, R.; Quantitative NMR for the structural analysis of novel bivalent glycoconjugates as vaccine candidates J. Pharm. Biomed. Anal. 214, 114721, (2022) DOI: 10.1016/j.jpba.2022.114721

Novel unimolecular bivalent glycoconjugates were assembled combining several functionalized capsular polysaccharides of Streptococcus pneumoniae and Neisseria meningitidis to a carrier protein by using an effective strategy based on the Ugi 4-component reaction. The development of multivalent glycoconjugates opens new opportunities in the field of vaccine design, but their high structural complexity involves new analytical challenges. Nuclear Magnetic Resonance has found wide applications in the characterization and impurity profiling of carbohydrate-based vaccines. Eight bivalent conjugates were studied by quantitative NMR analyzing the structural identity, the content of each capsular polysaccharide, the ratios between polysaccharides, the polysaccharide to protein ratios and undesirable contaminants. The qNMR technique involves experiments with several modified parameters for obtaining spectra with quantifiable signals. In addition, the achieved NMR results were combined with the results of colorimetric assay and Size Exclusion HPLC for assessing the protein content and free protein percentage, respectively. The application of quantitative NMR showed to be efficient to clear up the new structural complexities while allowing the quantitative assessment of the components.
Publikation

Vasco, A. V.; Ceballos, L. G.; Wessjohann, L. A.; Rivera, D. G.; Multicomponent functionalization of the octreotide peptide macrocyclic scaffold Eur. J. Org. Chem. 2022, e202200687, (2022) DOI: 10.1002/ejoc.202200687

The replacement of the disulfide bridge by other types of side chain linkages has been a continuous endeavor in the development of cyclic peptide drugs with improved metabolic stability. Octreotide is a potent and selective somatostatin analog that has been used as an anticancer agent, in radiolabeled conjugates for the localization of tumors and as targeting moiety in peptide-drug conjugates. Here, we describe an onresin methodology based on a multicomponent macrocyclization that enables the substitution of the disulfide bond by a tertiary lactam bridge functionalized with a variety of exocyclic moieties, including lipids, fluorophores, and charged groups. Conformational analysis in comparison with octreotide provides key information on the type of functionalization permitting the conformational mimicry of the bioactive peptide.
Bücher und Buchkapitel

Vasco, A. V.; Ricardo, M. G.; Rivera, D. G.; Wessjohann, L. A.; Ligation, Macrocyclization, and Simultaneous Functionalization of Peptides by Multicomponent Reactions (MCR) Methods Mol. Biol. 2371, 143-157, (2022) ISBN: 978-1-0716-1688-8 DOI: 10.1007/978-1-0716-1689-5_8

Multicomponent reactions (MCRs) are recently expanding the plethora of solid-phase protocols for the synthesis and derivatization of peptides. Herein, we describe a solid-phase-compatible strategy based on MCRs as a powerful strategy for peptide cyclization and ligation . We illustrate, using Gramicidin S as a model peptide, how the execution of on-resin Ugi reactions enables the simultaneous backbone N-functionalization and cyclization, which are important types of derivatizations in peptide-based drug development or for incorporation of conjugation handles, or labels.
Publikation

Méndez, Y.; Vasco, A. V.; Humpierre, A. R.; Westermann, B.; Isonitriles: Versatile handles for the bioorthogonal functionalization of proteins ACS Omega 5, 25505-25510, (2020) DOI: 10.1021/acsomega.0c03728

The property of the isonitrile group to enable the simultaneous α-addition of a strong electrophile and a nucleophile has always attracted the attention of organic chemists. Its versatility is augmented when recognizing that its high structural compactness, the inertia to most of the naturally occurring functional groups, and relatively prolonged physiological and metabolical stability, convert it into the smallest bioorthogonal group. The discovery and optimization of the isonitrile-tetrazine [4+1] cycloaddition as an alternative tool for the development of ligation and decaging strategies and the recently reported reaction of isonitriles with chlorooximes bring new opportunities for the utilization of this functional group in biological systems. Although several approaches have been reported for the synthesis of isonitrile-modified carbohydrates and polysaccharides, its incorporation in proteins has been barely explored. Besides compiling the reported methods for the assembly of isonitrile-modified proteins, this Mini-Review aims at calling attention to the real potential of this modification for protein ligation, decaging, immobilization, imaging, and many other applications at a low structural and functional cost.
Publikation

Humpierre, A. R.; Zanuy, A.; Saenz, M.; Garrido, R.; Vasco, A. V.; Pérez-Nicado, R.; Soroa-Milán, Y.; Santana-Mederos, D.; Westermann, B.; Vérez-Bencomo, V.; Méndez, Y.; García-Rivera, D.; Rivera, D. G.; Expanding the Scope of Ugi Multicomponent Bioconjugation to Produce Pneumococcal Multivalent Glycoconjugates as Vaccine Candidates Bioconjugate Chem. 31, 2231-2240, (2020) DOI: 10.1021/acs.bioconjchem.0c00423

Conjugate vaccines against encapsulated pathogens like Streptococcus pneumoniae face many challenges, including the existence of multiple serotypes with a diverse global distribution that constantly requires new formulations and higher coverage. Multivalency is usually achieved by combining capsular polysaccharide–protein conjugates from invasive serotypes, and for S. pneumoniae, this has evolved from 7- up to 20-valent vaccines. These glycoconjugate formulations often contain high concentrations of carrier proteins, which may negatively affect glycoconjugate immune response. This work broadens the scope of an efficient multicomponent strategy, leading to multivalent pneumococcal glycoconjugates assembled in a single synthetic operation. The bioconjugation method, based on the Ugi four-component reaction, enables the one-pot incorporation of two different polysaccharide antigens to a tetanus toxoid carrier, thus representing the fastest approach to achieve multivalency. The reported glycoconjugates incorporate three combinations of capsular polysaccharides 1, 6B, 14, and 18C from S. pneumoniae. The glycoconjugates were able to elicit functional specific antibodies against pneumococcal strains comparable to those shown by mixtures of the two monovalent glycoconjugates.
Publikation

Vasco, A. V.; Brode, M.; Méndez, Y.; Valdés, O.; Rivera, D. G.; Wessjohann, L. A.; Synthesis of Lactam-Bridged and Lipidated Cyclo-Peptides as Promising Anti-Phytopathogenic Agents Molecules 25, 811, (2020) DOI: 10.3390/molecules25040811

Antimicrobial resistance to conventional antibiotics and the limited alternatives to combat plant-threatening pathogens are worldwide problems. Antibiotic lipopeptides exert remarkable membrane activity, which usually is not prone to fast resistance formation, and often show organism-type selectivity. Additional modes of action commonly complement the bioactivity profiles of such compounds. The present work describes a multicomponent-based methodology for the synthesis of cyclic polycationic lipopeptides with stabilized helical structures. The protocol comprises an on solid support Ugi-4-component macrocyclization in the presence of a lipidic isocyanide. Circular dichroism was employed to study the influence of both macrocyclization and lipidation on the amphiphilic helical structure in water and micellar media. First bioactivity studies against model phytopathogens demonstrated a positive effect of the lipidation on the antimicrobial activity.
Publikation

Vasco, A. V.; Moya, C. G.; Gröger, S.; Brandt, W.; Balbach, J.; Pérez, C. S.; Wessjohann, L. A.; Rivera, D. G.; Insights into the secondary structures of lactam N-substituted stapled peptides Org. Biomol. Chem. 18, 3838-3842, (2020) DOI: 10.1039/D0OB00767F

Stapled peptides derived from the Ugi macrocyclization comprise a special class of cyclopeptides with an N-substituted lactam bridge cross-linking two amino acid side chains. Herein we report a comprehensive analysis of the structural factors influencing the secondary structure of these cyclic peptides in solution. Novel insights into the s-cis/s-trans isomerism and the effect of N-functionalization on the conformation are revealed.
Publikation

Vasco, A. V.; Méndez, Y.; Porzel, A.; Balbach, J.; Wessjohann, L. A.; Rivera, D. G.; A Multicomponent Stapling Approach to Exocyclic Functionalized Helical Peptides: Adding Lipids, Sugar, PEGs, Labels and Handles to the Lactam Bridge Bioconjugate Chem. 30, 253-259, (2019) DOI: 10.1021/acs.bioconjchem.8b00906

Peptide stapling is traditionally used to lock peptide conformations into α-helical structures using a variety of macrocyclization chemistries. In an endeavor to add a diversity-generating tool to this repertoire, we introduce a multicomponent stapling approach enabling the simultaneous stabilization of helical secondary structures and the exocyclic N-functionalization of the side chain-tethering lactam bridge. This is accomplished by means of a novel solid-phase methodology comprising, for the first time, the on-resin Ugi reaction-based macrocyclization of peptide side chains bearing amino and carboxylic acid groups. The exocyclic diversity elements arise from the isocyanide component used in the Ugi multicomponent stapling protocol, which allows for the incorporation of relevant fragments such as lipids, sugars, polyethylene glycol, fluorescent labels, and reactive handles. We prove the utility of such exocyclic reactive groups in the bioconjugation of a maleimide-armed lactam-bridged peptide to a carrier protein. The on-resin multicomponent stapling proved efficient for the installation of not only one, but also two consecutive lactam bridges having either identical or dissimilar N-functionalities. The easy access to helical peptides with a diverse set of exocyclic functionalities shows prospect for applications in peptide drug discovery and chemical biology.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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