Modification of the carbohydrate scaffold is an important theme in drug and vaccine discovery. Therefore, the preparation of novel types of glycomimetics is of interest in synthetic carbohydrate chemistry. In this manuscript, we present an early investigation of the synthesis, structure, and conformational behaviour of (1→1)-Si-disaccharides as a novel type of glycomimetics arising from the replacement of interglycosidic oxygen with a dimethyl-, methylpropyl-, or diisopropylsilyl linkage. We accomplished the preparation of this unusual group of umpoled compounds by the reaction of lithiated glycal or 2-oxyglycal units with dialkyldichlorosilanes. We demonstrated the good stability of the "Si-glycosidic" linkage under acidic conditions even at elevated temperatures. Next, we described the conformational landscape of these compounds by the combination of in silico modelling with spectroscopic and crystallographic methods. Finally, we explained the observed conformational flexibility of these compounds by the absence of gauche stabilizing effects that are typically at play in natural carbohydrates.
The Photorhabdus species is a Gram-negative bacteria of the family Morganellaceae that is known for its mutualistic relationship with Heterorhabditis nematodes and pathogenicity toward insects. This study is focused on the characterization of the recombinant lectin PLL3 with an origin in P. laumondii subsp. laumondii. PLL3 belongs to the PLL family of lectins with a seven-bladed β-propeller fold. The binding properties of PLL3 were tested by hemagglutination assay, glycan array, isothermal titration calorimetry, and surface plasmon resonance, and its structure was determined by X-ray crystallography. Obtained data revealed that PLL3 binds similar carbohydrates to those that the other PLL family members bind, with some differences in the binding properties. PLL3 exhibited the highest affinity toward l-fucose and its derivatives but was also able to interact with O-methylated glycans and other ligands. Unlike the other members of this family, PLL3 was discovered to be a monomer, which might correspond to a weaker avidity effect compared to homologous lectins. Based on the similarity to the related lectins and their proposed biological function, PLL3 might accompany them during the interaction of P. laumondii with both the nematode partner and the insect host.
- MeSH
- bakteriální proteiny chemie genetika metabolismus MeSH
- fruktosa metabolismus MeSH
- kalorimetrie MeSH
- krystalografie rentgenová MeSH
- lektiny chemie genetika metabolismus MeSH
- Photorhabdus metabolismus MeSH
- povrchová plasmonová rezonance MeSH
- rekombinantní proteiny chemie metabolismus MeSH
- sekundární struktura proteinů MeSH
- vazebná místa MeSH
- Publikační typ
- časopisecké články MeSH
A recently described bangle lectin (PHL) from the bacterium Photorhabdus asymbiotica was identified as a mainly fucose-binding protein that could play an important role in the host-pathogen interaction and in the modulation of host immune response. Structural studies showed that PHL is a homo-dimer that contains up to seven L-fucose-specific binding sites per monomer. For these reasons, potential ligands of the PHL lectin: α-L-fucopyranosyl-containing mono-, di-, tetra-, hexa- and dodecavalent ligands were tested. Two types of polyvalent structures were investigated - calix[4]arenes and dendrimers. The shared feature of all these structures was a C-glycosidic bond instead of the more common but physiologically unstable O-glycosidic bond. The inhibition potential of the tested structures was assessed using different techniques - hemagglutination, surface plasmon resonance, isothermal titration calorimetry, and cell cross-linking. All the ligands proved to be better than free L-fucose. The most active hexavalent dendrimer exhibited affinity three orders of magnitude higher than that of standard L-fucose. To determine the binding mode of some ligands, crystal complex PHL/fucosides 2 - 4 were prepared and studied using X-ray crystallography. The electron density in complexes proved the presence of the compounds in 6 out of 7 fucose-binding sites.
- MeSH
- antibakteriální látky chemie farmakologie terapeutické užití MeSH
- bakteriální infekce farmakoterapie mikrobiologie MeSH
- bakteriální proteiny antagonisté a inhibitory chemie izolace a purifikace metabolismus MeSH
- dendrimery chemie farmakologie terapeutické užití MeSH
- erytrocyty MeSH
- fukosa analogy a deriváty farmakologie terapeutické užití MeSH
- hemaglutinace účinky léků MeSH
- interakce hostitele a patogenu účinky léků MeSH
- krystalografie rentgenová MeSH
- lektiny antagonisté a inhibitory chemie izolace a purifikace metabolismus MeSH
- lidé MeSH
- ligandy MeSH
- molekulární modely MeSH
- Photorhabdus metabolismus MeSH
- povrchová plasmonová rezonance MeSH
- rekombinantní proteiny chemie izolace a purifikace metabolismus MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Conformational preferences of two C-glycosyl analogues of Manp-(1 → 3)-Manp, were studied using a combined method of theoretical and experimental chemistry. Molecular dynamics was utilized to provide conformational behavior along C-glycosidic bonds of methyl 3-deoxy-3-C-[(α-d-mannopyranosyl)methyl]-α-d- and l-mannopyranosides. The OPLS2005 and Glycam06 force fields were used. Simulations were performed with explicit water (TIP3P) and methanol. Results were compared with a complete conformational scan at the MM4 level with the dielectric constant corresponding to methanol. In order to verify predicted conformational preferences, vicinal 3JHH NMR coupling constants were calculated by the Karplus equation on simulated potential energy surfaces (PES). A set of new parameters for the Karplus equation was also designed. Predicted 3JHH were compared with experimental data. We also used reverse methodology, in which the 3JHH coupling constants were calculated at the DFT level for each family of (ϕ, ψ)-conformers separately and then experimental values were decomposed onto calculated 3JHH couplings in order to obtain experimentally derived populations of conformers. As an alternative method of evaluation of preferred conformers, analysis of sensitive 13C chemical shifts was introduced. We were able to thoroughly discuss several fundamental issues in predictions of preferred conformers of C-saccharides, such as the solvent effect, reliability of the force field, character of empirical Karplus equation or applicability of NMR parameters in predictions of conformational preferences in general.
The C-type lectin DC-SIGN expressed on immature dendritic cells is a promising target for antiviral drug development. Previously, we have demonstrated that mono- and divalent C-glycosides based on d-manno and l-fuco configurations are promising DC-SIGN ligands. Here, we described the convergent synthesis of C-glycoside dendrimers decorated with 4, 6, 9, and 12 α-l-fucopyranosyl units and with 9 and 12 α-d-mannopyranosyl units. Their affinity against DC-SIGN was assessed by surface plasmon resonance (SPR) assays. For comparison, parent O-glycosidic dendrimers were synthesized and tested, as well. A clear increase of both affinity and multivalency effect was observed for C-glycomimetics of both types (mannose and fucose). However, when dodecavalent C-glycosidic dendrimers were compared, there was no difference in affinity regarding the sugar unit (l-fuco, IC50 17 μM; d-manno, IC50 12 μM). For the rest of glycodendrimers with l-fucose or d-mannose attached by the O- or C-glycosidic linkage, C-glycosidic dendrimers were significantly more active. These results show that in addition to the expected physiological stability, the biological activity of C-glycoside mimetics is higher in comparison to the corresponding O-glycosides and therefore these glycomimetic multivalent systems represent potentially promising candidates for targeting DC-SIGN.
- MeSH
- biomimetické materiály chemie farmakologie MeSH
- fukosa chemie MeSH
- inhibiční koncentrace 50 MeSH
- lektiny typu C antagonisté a inhibitory MeSH
- mannosa chemie MeSH
- molekuly buněčné adheze antagonisté a inhibitory MeSH
- receptory buněčného povrchu antagonisté a inhibitory MeSH
- Publikační typ
- časopisecké články MeSH
The discovery of effective ligands for DC-SIGN receptor is one of the most challenging concepts of antiviral drug design due to the importance of this C-type lectin in infection processes. DC-SIGN recognizes mannosylated and fucosylated oligosaccharides but glycosidic linkages are accessible to both chemical and enzymatic degradations. To avoid this problem, the synthesis of stable glycoside mimetics has attracted increasing attention. In this work we establish for the first time mono- and divalent C-glycosides based on d-manno and l-fuco configurations as prospective DC-SIGN ligands. In particular, the l-fucose glycomimetics were more active than the respective d-mannose ones. The highest affinity was assessed for simple 1,4-bis(α-l-fucopyranosyl)butane (SPR: IC50 0.43 mM) that displayed about twice higher activity than natural ligand Le(x). Our results make C-glycosides attractive candidates for multivalent presentations.
- MeSH
- biomimetika MeSH
- fukosa chemie MeSH
- glykosidy chemická syntéza chemie MeSH
- lektiny typu C chemie metabolismus MeSH
- lidé MeSH
- mannosa chemie MeSH
- molekulární struktura MeSH
- molekuly buněčné adheze chemie metabolismus MeSH
- receptory buněčného povrchu chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
In an effort to identify an HIV-1 capsid assembly inhibitor with improved solubility and potency, we synthesized two series of pyrimidine analogues based on our earlier lead compound N-(4-(ethoxycarbonyl)phenyl)-2-(pyridine-4-yl)quinazoline-4-amine. In vitro binding experiments showed that our series of 2-pyridine-4-ylpyrimidines had IC50 values higher than 28μM. Our series of 2-pyridine-3-ylpyrimidines exhibited IC50 values ranging from 3 to 60μM. The congeners with a fluoro substituent introduced at the 4-N-phenyl moiety, along with a methyl at C-6, represent potent HIV capsid assembly inhibitors binding to the C-terminal domain of the capsid protein.
- MeSH
- HIV-1 účinky léků metabolismus MeSH
- kapsida chemie metabolismus MeSH
- látky proti HIV chemická syntéza chemie farmakologie MeSH
- mikrobiální testy citlivosti MeSH
- molekulární struktura MeSH
- pyrimidiny chemická syntéza chemie farmakologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
Assembly of human immunodeficiency virus (HIV-1) represents an attractive target for antiretroviral therapy which is not exploited by currently available drugs. We established high-throughput screening for assembly inhibitors based on competition of small molecules for the binding of a known dodecapeptide assembly inhibitor to the C-terminal domain of HIV-1 CA (capsid). Screening of >70000 compounds from different libraries identified 2-arylquinazolines as low micromolecular inhibitors of HIV-1 capsid assembly. We prepared focused libraries of modified 2-arylquinazolines and tested their capacity to bind HIV-1 CA to compete with the known peptide inhibitor and to prevent the replication of HIV-1 in tissue culture. Some of the compounds showed potent binding to the C-terminal domain of CA and were found to block viral replication at low micromolar concentrations.
- MeSH
- chinazoliny chemická syntéza chemie farmakologie MeSH
- HIV-1 účinky léků metabolismus MeSH
- kapsida účinky léků metabolismus MeSH
- knihovny malých molekul MeSH
- látky proti HIV metabolismus farmakologie MeSH
- lidé MeSH
- molekulární modely MeSH
- rekombinantní proteiny biosyntéza MeSH
- replikace viru účinky léků MeSH
- reprodukovatelnost výsledků MeSH
- rychlé screeningové testy MeSH
- termodynamika MeSH
- viabilita buněk účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
An approach to stereoselective synthesis of alpha- or beta-3-C-glycosylated L- or D-1,2-glucals starting from the corresponding alpha- or beta-glycopyranosylethanals is described. The key step of the approach is the stereoselective cycloaddition of chiral vinyl ethers derived from both enantiomers of mandelic acid. The preparation of 1,5-anhydro-4,6-di-O-benzyl-2,3-dideoxy-3-C-[(2,3,4,6-tetra-O-benzyl-beta-D-glucopyranosyl)methyl]-L-arabino-hex-1-enitol, 1,5-anhydro-4,6-di-O-benzyl-2,3-dideoxy-3-C-[(2,3,4,6-tetra-O-benzyl-beta-D-glucopyranosyl)methyl]-D-arabino-hex-1-enitol, and 1,5-anhydro-4,6-di-O-benzyl-2,3-dideoxy-3-C-[(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)methyl]-D-arabino-hex-1-enitol serves as an example of this approach.
