Linkers
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Amine-containing drugs often show poor pharmacological properties, but these disadvantages can be overcome by using a prodrug approach involving self-immolative linkers. Accordingly, we designed l-lactate linkers as ideal candidates for amine delivery. Furthermore, we designed linkers bearing two different cargos (aniline and phenol) for preferential amine cargo release within 15 min. Since the linkers carrying secondary amine cargo showed high stability at physiological pH, we used our strategy to prepare phosphate-based prodrugs of the antibiotic Ciprofloxacin. Therefore, our study will facilitate the rational design of new and more effective drug delivery systems for amine-containing drugs.
- MeSH
- aminy chemie MeSH
- antibakteriální látky chemie MeSH
- ciprofloxacin chemie MeSH
- fosfáty chemie MeSH
- koncentrace vodíkových iontů MeSH
- kyselina mléčná chemie MeSH
- léčivé přípravky chemie MeSH
- lékové transportní systémy metody MeSH
- prekurzory léčiv chemie MeSH
- Publikační typ
- časopisecké články MeSH
N-methyl-D-aspartate receptors (NMDARs) mediate excitatory synaptic transmission in the central nervous system, underlie the induction of synaptic plasticity, and their malfunction is associated with human diseases. Native NMDARs are tetramers composed of two obligatory GluN1 subunits and various combinations of GluN2A-D or, more rarely, GluN3A-B subunits. Each subunit consists of an amino-terminal, ligand-binding, transmembrane and carboxyl-terminal domain. The ligand-binding and transmembrane domains are interconnected via polypeptide chains (linkers). Upon glutamate and glycine binding, these receptors undergo a series of conformational changes leading to the opening of the Ca2+-permeable ion channel. Here we report that different deletions and mutations of amino acids in the M3-S2 linkers of the GluN1 and GluN2B subunits lead to constitutively open channels. Irrespective of whether alterations were introduced in the GluN1 or the GluN2B subunit, application of glutamate or glycine promoted receptor channel activity; however, responses induced by the GluN1 agonist glycine were larger, on average, than those induced by glutamate. We observed the most prominent effect when residues GluN1(L657) and GluN2B(I655) were deleted or altered to glycine. In parallel, molecular modeling revealed that two interacting pairs of residues, the LILI motif (GluN1(L657) and GluN2B(I655)), form a functional unit with the TTTT ring (GluN1(T648) and GluN2B(T647)), described earlier to control NMDAR channel gating. These results provide new insight into the structural organization and functional interplay of the LILI and the TTTT ring during the course of NMDAR channel opening and closing.
- Publikační typ
- časopisecké články MeSH
Nitrile imines produced by photodissociation of 2,5-diaryltetrazoles undergo cross-linking reactions with amide groups in peptide-tetrazole (tet-peptide) conjugates and a tet-peptide-dinucleotide complex. Tetrazole photodissociation in gas-phase ions is efficient, achieving ca. 50% conversion with 2 laser pulses at 250 nm. The formation of cross-links was detected by CID-MS3 that showed structure-significant dissociations by loss of side-chain groups and internal peptide segments. The structure and composition of cross-linking products were established by a combination of UV-vis action spectroscopy and cyclic ion mobility mass spectrometry (c-IMS). The experimental absorption bands were found to match the bands calculated for vibronic absorption spectra of nitrile imines and cross-linked hydrazone isomers. The calculated collision cross sections (CCSth) for these ions were related to the matching experimental CCSexp from multipass c-IMS measurements. Loss of N2 from tet-peptide conjugates was calculated to be a mildly endothermic reaction with ΔH0 = 80 kJ mol-1 in the gas phase. The excess energy in the photolytically formed nitrile imine is thought to drive endothermic proton transfer, followed by exothermic cyclization to a sterically accessible peptide amide group. The exothermic nitrile imine reaction with peptide amides is promoted by proton transfer and may involve an initial [3 + 2] cycloaddition followed by cleavage of the oxadiazole intermediate. Nucleophilic groups, such as cysteine thiol, did not compete with the amide cyclization. Nitrile imine cross-linking to 2'-deoxycytidylguanosine was found to be >80% efficient and highly specific in targeting guanine. The further potential for exploring nitrile-imine cross-linking for biomolecular structure analysis is discussed.
BACKGROUND: The design of new heterodimeric dual binding site acetylcholinesterase inhibitors constitutes the main goal-directed to the development of new anticholinesterase agents with the expanded pharmacological profile. Multi-target compounds are usually designed by combining in a hybrid molecule with two or more pharmacophoric moieties that are known to enable interaction with the selected molecular targets. METHODS: All compounds were tested for their inhibitory activity on human AChE/BChE. The Ellman´s method was used to determine inhibition kinetics and IC50 values. In order to predict passive bloodbrain penetration of novel compounds, modification of the parallel artificial membrane permeation assay has been used. Docking studies were performed in order to predict the binding modes of new hybrids with hAChE/ hBChE respectively. RESULTS: In this study, we described the design, synthesis, and evaluation of series tacrine-coumarin and tacrine-quinoline compounds which were found to show potential inhibition of ChEs and penetration of the blood-brain barrier. CONCLUSION: Tacrine-quinoline hybrids 7a exhibited the highest activity towards hBChE (IC50 = 0.97 µmol) and 7d towards hAChE (IC50 = 0.32 µmol). Kinetic and molecular modelling studies revealed that 7d was a mixed-type AChE inhibitor (Ki = 1.69 µmol) and 7a was a mixed-type BChE inhibitor (Ki = 1.09 µmol). Moreover, hybrid 5d and 7c could penetrate the CNS.
- MeSH
- cholinesterasové inhibitory chemie farmakologie MeSH
- hematoencefalická bariéra účinky léků MeSH
- kinetika MeSH
- kumariny chemie farmakologie MeSH
- lidé MeSH
- molekulární modely MeSH
- permeabilita účinky léků MeSH
- simulace molekulového dockingu MeSH
- takrin chemie farmakologie MeSH
- thiomočovina chemie farmakologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A new series of substituted tacrine/acridine and tacrine/tacrine dimers with aliphatic or alkylene-thiourea linkers was synthesized and the potential of these compounds as novel human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE) inhibitors with nanomolar inhibition activity was evaluated. The most potent AChE inhibitor was found to be homodimeric tacrine derivative 14a, which demonstrated an IC50 value of 2 nM; this value indicates an activity rate which is 250-times higher than that of tacrine 1 and 7500-times higher than 7-MEOTA 15, the compounds which were used as standards in the study. IC50 values of derivatives 1, 9, 10, 14b and 15 were compared with the dissociation constants of the enzyme-inhibitor complex, Ki1, and the enzyme-substrate-inhibitor complex, Ki2, for. A dual binding site is presumed for the synthesized compounds which possess two tacrines or tacrine and acridine as terminal moieties show evidence of dual site binding. DFT calculations of theoretical desolvation free energies, ΔΔGtheor, and docking studies elucidate these suggestions in more detail.
- MeSH
- acetylcholinesterasa chemie metabolismus MeSH
- akridiny chemie MeSH
- aktivace enzymů účinky léků MeSH
- butyrylcholinesterasa chemie metabolismus MeSH
- cholinesterasové inhibitory chemie farmakologie MeSH
- lidé MeSH
- molekulární konformace MeSH
- molekulární modely MeSH
- piperaziny chemie MeSH
- takrin chemie MeSH
- thiomočovina chemie MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
To develop potent and selective nNOS inhibitors, a new series of double-headed molecules with chiral linkers that derive from natural amino acid derivatives have been designed and synthesized. The new structures integrate a thiophenecarboximidamide head with two types of chiral linkers, presenting easy synthesis and good inhibitory properties. Inhibitor (S)-9b exhibits a potency of 14.7 nM against nNOS and is 1134 and 322-fold more selective for nNOS over eNOS and iNOS, respectively. Crystal structures show that the additional binding between the aminomethyl moiety of 9b and propionate A on the heme and tetrahydrobiopterin (H4B) in nNOS, but not eNOS, contributes to its high selectivity. This work demonstrates the advantage of integrating known structures into structure optimization, and it should be possible to more readily develop compounds that incorporate bioavailability with these advanced features. Moreover, this integrative strategy is a general approach in new drug discovery.
- MeSH
- imidy chemická syntéza chemie farmakologie MeSH
- inhibitory enzymů chemická syntéza chemie farmakologie MeSH
- molekulární modely MeSH
- molekulární struktura MeSH
- synthasa oxidu dusnatého, typ I antagonisté a inhibitory metabolismus MeSH
- thiofeny chemická syntéza chemie farmakologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Organic dye-tagged lipid analogs are essential for many fluorescence-based investigations of complex membrane structures, especially when using advanced microscopy approaches. However, lipid analogs may interfere with membrane structure and dynamics, and it is not obvious that the properties of lipid analogs would match those of non-labeled host lipids. In this work, we bridged atomistic simulations with super-resolution imaging experiments and biomimetic membranes to assess the performance of commonly used sphingomyelin-based lipid analogs. The objective was to compare, on equal footing, the relative strengths and weaknesses of acyl chain labeling, headgroup labeling, and labeling based on poly-ethyl-glycol (PEG) linkers in determining biomembrane properties. We observed that the most appropriate strategy to minimize dye-induced membrane perturbations and to allow consideration of Brownian-like diffusion in liquid-ordered membrane environments is to decouple the dye from a membrane by a PEG linker attached to a lipid headgroup. Yet, while the use of PEG linkers may sound a rational and even an obvious approach to explore membrane dynamics, the results also suggest that the dyes exploiting PEG linkers interfere with molecular interactions and their dynamics. Overall, the results highlight the great care needed when using fluorescent lipid analogs, in particular accurate controls.
The primary objective was to understand more deeply the molecular mechanism underlying different antitumor effects of dinuclear Pt(II) complexes containing aromatic linkers of different length, {[cis-Pt(NH(3))(2)Cl](2)(4,4'-methylenedianiline)}(2+) (1) and {[cis-Pt(NH(3))(2)Cl](2)(alpha,alpha'-diamino-p-xylene)}(2+) (2). These complexes belong to a new generation of promising polynuclear platinum drugs resistant to decomposition by sulfur nucleophiles which hampers clinical use of bifunctional polynuclear trans Pt(II) complexes hitherto tested. Results obtained with the aid of methods of molecular biophysics and pharmacology reveal differences and new details of DNA modifications by 1 and 2 and recognition of these modifications by cellular components. The results indicate that the unique properties of DNA interstrand cross-links of this class of polynuclear platinum complexes and recognition of these cross-links may play a prevalent role in antitumor effects of these metallodrugs. Moreover, the results show for the first time a strong specific recognition and binding of high-mobility-group-domain proteins, which are known to modulate antitumor effects of clinically used platinum drugs, to DNA modified by a polynuclear platinum complex.
- MeSH
- adukty DNA chemie metabolismus MeSH
- cisplatina chemie metabolismus farmakologie MeSH
- HeLa buňky MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- poškození DNA účinky léků fyziologie MeSH
- protinádorové látky chemie metabolismus farmakologie MeSH
- reagencia zkříženě vázaná chemie metabolismus farmakologie MeSH
- viabilita buněk účinky léků fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Microtubule dynamic is exceptionally sensitive to modulation by small-molecule ligands. Our previous work presented the preparation of microtubule-targeting estradiol dimer (ED) with anticancer activity. In the present study, we explore the effect of selected linkers on the biological activity of the dimer. The linkers were designed as five-atom chains with carbon, nitrogen or oxygen in their centre. In addition, the central nitrogen was modified by a benzyl group with hydroxy or methoxy substituents and one derivative possessed an extended linker length. Thirteen new dimers were subjected to cytotoxicity assay and cell cycle profiling. Dimers containing linker with benzyl moiety substituted with one or more methoxy groups and longer branched ones were found inactive, whereas other structures had comparable efficacy as the original ED (e.g. D1 with IC50 = 1.53 μM). Cell cycle analysis and immunofluorescence proved the interference of dimers with microtubule assembly and mitosis. The proposed in silico model and calculated binding free energy by the MM-PBSA method were closely correlated with in vitro tubulin assembly assay.
- MeSH
- apoptóza MeSH
- ethinylestradiol * chemie farmakologie MeSH
- kontrolní body fáze G2 buněčného cyklu účinky léků MeSH
- mikrotubuly MeSH
- modulátory tubulinu * chemie farmakologie MeSH
- nádorové buněčné linie MeSH
- protinádorové látky * chemie farmakologie MeSH
- triazoly * chemie farmakologie MeSH
- tubulin * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We have designed, synthesized, and characterized peptides containing four repeats of the sequences VAALEKE (peptide E) or VAALKEK (peptide K). While the peptides alone adopt in aqueous solutions a random coil conformation, their equimolar mixture forms heterodimeric coiled coils as confirmed by CD spectroscopy. 5-Azidopentanoic acid was connected to the N-terminus of peptide E via a short poly(ethylene glycol) spacer. The terminal azide group enabled conjugation of the peptide with a synthetic drug carrier based on the N-(2-hydroxypropyl)methacrylamide copolymer containing propargyl groups using "click" chemistry. When incorporated into the polymer drug carrier, peptide E formed a stable noncovalent complex with peptide K belonging to a recombinant single-chain fragment (scFv) of the M75 antibody. The complex thereby mediates a noncovalent linkage between the polymer drug carrier and the protein. The recombinant scFv antibody fragment was selected as a targeting ligand against carbonic anhydrase IX-a marker overexpressed by tumor cells of various human carcinomas. The antigen binding affinity of the polymer-scFv complex was confirmed by ELISA. This approach offers a well-defined, specific, and nondestructive universal method for the preparation of protein (antibody)-targeted polymer drug and gene carriers designed for cell-specific delivery.
- MeSH
- akrylamidy chemie MeSH
- antigeny nádorové imunologie metabolismus MeSH
- bakteriální transformace MeSH
- cirkulární dichroismus MeSH
- click chemie metody MeSH
- dimerizace MeSH
- ELISA MeSH
- Escherichia coli MeSH
- imunokonjugáty chemie imunologie farmakologie MeSH
- karboanhydrasy imunologie metabolismus MeSH
- karcinom farmakoterapie enzymologie imunologie patologie MeSH
- klonování DNA MeSH
- lidé MeSH
- molekulární konformace MeSH
- monoklonální protilátky chemie genetika imunologie MeSH
- nádorové biomarkery imunologie metabolismus MeSH
- nosiče léků chemická syntéza farmakologie MeSH
- oligopeptidy chemická syntéza imunologie farmakologie MeSH
- plazmidy MeSH
- polyethylenglykoly chemie MeSH
- rekombinantní proteiny chemie genetika imunologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
