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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

Hernández, G.; Ramos, B.; Sultani, H. N.; Ortiz, Y.; Spengler, I.; Castañeda, R. F.; Rivera, D. G.; Arnold, N.; Westermann, B.; Mirabal, Y.; Cultural characterization and antagonistic activity of Cladobotryum virescens against some phytopathogenic fungi and oomycetes Agronomy 13, 389, (2023) DOI: 10.3390/agronomy13020389

In this study, the characteristic growth of Cladobotryum virescens on nine culture media was analyzed. The growing behavior of this fungus was dependent on the culture medium. In vitro analysis showed that oat agar was better than other media tested with the highest conidia production. The antifungal activity against Fusarium chlamydosporum and Alternaria brassicicola was evaluated by the Dual Culture method. C. virescens displayed high activity against both pathogens acting through antibiosis and mycoparasitism. This effect was increased by a higher competitiveness of the strain for the substrate. Furthermore, the crude ethyl acetate extract of the culture broth was tested in vitro against Botrytis cinerea and Septoria tritici, as well as the hemibiotrophic oomycete Phytophthora infestans using a microtiter plate assay at different concentrations. The extract showed excellent inhibition even below 5 ppm. According to these results, we concluded that C. virescens can be considered as a potential biological control agent in agriculture. To the best of our knowledge, this is the first study to investigate C. virescens as a biocontrol agent for different diseases caused by five relevant pathogens that affect cereals and vegetables.
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

González-Bacerio, J.; Varela, A. C.; Aguado, M. E.; Izquierdo, M.; Méndez, Y.; del Rivero, M. A.; Rivera, D. G.; Bacterial metalo-aminopeptidases as targets in human infectious diseases Current Drug Targets 23, 1155-1190, (2022) DOI: 10.2174/1389450123666220316085859

Background: Human infectious diseases caused by bacteria are a worldwide health problem due to the increased resistance of these microorganisms to conventional antibiotics. For this reason, the identification of novel molecular targets and the discovery of new antibacterial compounds is urgently required. Metalo-aminopeptidases are promising targets in bacterial infections. They participate in crucial processes for bacterial growth and pathogenesis, such as protein and peptide degradation to supply amino acids, protein processing, access to host tissues, cysteine supply for redox control, transcriptional regulation, site-specific DNA recombination, and hydrogen sulfide production. Although several of these enzymes are not essential, they are required for virulence and maximal growth in conditions of nutrient limitation and high temperatures.Objective: In this review, we describe the structural, functional and kinetic properties of some examples of bacterial metalo-aminopeptidases, in the context of their use as antibacterial targets. In addition, we present some inhibitors reported for these enzymes.Conclusion: It is necessary a meticulous work to validate these peptidases as good/bad targets and to identify inhibitors with a potential therapeutic use.
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

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

Ricardo, M. G.; Moya, C. G.; Pérez, C. S.; Porzel, A.; Wessjohann, L. A.; Rivera, D. G.; Improved Stability and Tunable Functionalization of Parallel β‐Sheets via Multicomponent N‐Alkylation of the Turn Moiety Angew. Chem. 132, 265-269, (2020) DOI: 10.1002/ange.201912095

In contrast to the myriad of methods available to produce α‐helices and antiparallel β‐sheets in synthetic peptides, just a few are known for the construction of stable, non‐cyclic parallel β‐sheets. Herein, we report an efficient on‐resin approach for the assembly of parallel β‐sheet peptides in which the N‐alkylated turn moiety enhances the stability and gives access to a variety of functionalizations without modifying the parallel strands. The key synthetic step of this strategy is the multicomponent construction of an N‐alkylated turn using the Ugi reaction on varied isocyano‐resins. This four‐component process assembles the orthogonally protected turn fragment and incorporates handles serving for labeling/conjugation purposes or for reducing peptide aggregation. NMR and circular dichroism analyses confirm the better‐structured and more stable parallel β‐sheets in the N‐alkylated peptides compared to the non‐functionalized variants.
Publikation

Ricardo, M. G.; Moya, C. G.; Pérez, C. S.; Porzel, A.; Wessjohann, L. A.; Rivera, D. G.; Improved Stability and Tunable Functionalization of Parallel β-Sheets via Multicomponent N-Alkylation of the Turn Moiety Angew. Chem. Int. Ed. 59, 259-263, (2020) DOI: 10.1002/anie.201912095

In contrast to the myriad of methods available to produce α‐helices and antiparallel β‐sheets in synthetic peptides, just a few are known for the construction of stable, non‐cyclic parallel β‐sheets. Herein, we report an efficient on‐resin approach for the assembly of parallel β‐sheet peptides in which the N‐alkylated turn moiety enhances the stability and gives access to a variety of functionalizations without modifying the parallel strands. The key synthetic step of this strategy is the multicomponent construction of an N‐alkylated turn using the Ugi reaction on varied isocyano‐resins. This four‐component process assembles the orthogonally protected turn fragment and incorporates handles serving for labeling/conjugation purposes or for reducing peptide aggregation. NMR and circular dichroism analyses confirm the better‐structured and more stable parallel β‐sheets in the N‐alkylated peptides compared to the non‐functionalized variants.
  • Die Leibniz-Gemeinschaft
  • Digitalisierung in der Landwirtschaft
  • Martin-Luther Universität Halle
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