Search results for "Imides"
showing 10 items of 59 documents
Involvement of carboxyl groups in chloride transport and reversible DIDS binding to band 3 protein in human erythrocytes
2011
AbstractNoncovalent DIDS binding to Band 3 (AE1) protein in human erythrocyte membranes, modified by non-penetrating, water soluble 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)-carbodiimide iodide (EAC), was studied at 0°C in the presence of 165 mM KCl. Under experimental conditions applied up to (48 ± 5) % of irreversible chloride self-exchange inhibition was observed. The apparent dissociation constant, KD, for “DIDS-Band 3” complex, determined from the chloride transport experiments, was (34 ± 3) nM and (80 ± 12) nM for control and EAC-treated resealed ghosts, respectively. The inhibition constant, Ki, for DIDS was (35 ± 6) nM and (60 ± 8) nM in control and EAC-treated ghosts, respectively. T…
Highly efficient transport of carboxyfluorescein diacetate succinimidyl ester into COS7 cells using human papillomavirus-like particles
2003
AbstractHuman papillomavirus virus-like particles (VLPs) have recently been used to deliver genes into mammalian cells in vitro and in vivo. Here, we investigated whether VLPs may serve as an efficient carrier of low molecular weight compounds (e.g. hormones, vitamins, peptides etc.) into cells. COS7 cells were incubated with recombinant HPV-16L1/L2 VLPs labelled with the fluorescence dye carboxyfluorescein diacetate succinimidyl ester. Using flow cytometry, we demonstrate that labelled VLPs can specifically bind to the cell surface followed by their complete internalisation. Our results indicate that VLPs are promising vehicles for highly efficient delivery of low molecular weight compound…
Synthesis and in Vitro Evaluation of Biotinylated RG108: A High Affinity Compound for Studying Binding Interactions with Human DNA Methyltransferases
2006
Small-molecule inhibitors of DNA methyltransferases such as RG108 represent promising candidates for cancer drug development. We report the synthesis and in vitro analysis of a biotinylated RG108 conjugate, 2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-3-(5-[3-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)pentanoylamino]propoxy]-1H-indol-3-yl)propionic acid (bio-RG108), for the evaluation of interactions with DNA methyltransferase enzymes. The structural design of the chemically modified inhibitor was aided by molecular modeling, which suggested the possibility for extensive chemical modifications at the 5-position of the tryptophan moiety in RG108. The inhibitory activity of the corresponding d…
Diacylglycerols containing Omega 3 and Omega 6 fatty acids bind to RasGRP and modulate MAP kinase activation.
2003
We elucidated the effects of different diacylglycerols (DAGs), i.e. 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG), 1-stearoyl-2-docosahexaenoyl-sn-glycerol (SDG), and 1-stearoyl-2-eicosapentaenoyl-sn-glycerol (SEG), on [3H]PDBu binding to RasGRP. The competition studies with these DAGs on [3H]PDBu binding to RasGRP revealed different Ki values for these DAG molecular species. Furthermore, we transfected human Jurkat T cells by a plasmid containing RasGRP and assessed the implication of endogenous DAGs on activation of MAP kinases ERK1/ERK2, induced by phorbol-12-myristate-13-acetate (PMA). In control cells, GF109203X, a protein kinase C inhibitor, inhibited ERK1/ERK2 activation. However, this…
Fluorescent organometallic rhodium(I) and ruthenium(II) metallodrugs with 4-ethylthio-1,8-naphthalimide ligands: Antiproliferative effects, cellular …
2018
Fluorescent 4-ethylthio-1,8-naphthalimides containing rhodium(I) N-heterocyclic carbene (NHC) and ruthenium (II) NHC fragments were synthesised and evaluated for their antiproliferative effects, cellular uptake and DNA-binding activity. Both types of organometallics triggered ligand dependent efficient cytotoxic effects against tumor cells with the rhodium(I) NHC derivatives causing stronger effects than the ruthenium (II) NHC analogues. Antiproliferative effects could also be observed against several pathogenic Gram-positive bacterial strains, whereas the growth of Gram-negative bacteria was not substantially affected. Cellular uptake was confirmed by atomic absorption spectroscopy as well…
In situ synthesis of lipopeptides as versatile receptors for the specific binding of nanoparticles and liposomes to solid-supported membranes.
2008
A detailed study of the in situ coupling of small peptides such as CGGH6 (H6) and CGWK8 (K8) to maleimide functionalized phospholipid bilayers is presented. Individually addressable microstructured membranes are employed to unequivocally probe the conjugation. The in situ coupling of peptides via a terminal cysteine moiety to maleimide functionalized phospholipids is shown to be a convenient and versatile way to selectively fabricate peptide-modified phospholipid bilayers serving as specific receptor platforms for functionalized vesicles and nanoparticles. Specific binding of functional vesicles to the peptide-modified bilayers is achieved by either histidine complexation with Ni-NTA-DOGS c…
Coupling of Contact Sensitizers to Thiol Groups is a Key Event for the Activation of Monocytes and Monocyte-Derived Dendritic Cells
2003
Strong contact sensitizers are able to induce distinct signal transduction mechanisms in antigen-presenting cells by coupling to cell proteins. The predominant target structures of haptens are thought to be thiol and amino groups in cysteine and lysine residues. We studied whether coupling of small reactive chemicals to thiol or amino groups might be responsible for the activation of monocytes and mature monocyte-derived dendritic cells. Human peripheral blood mononuclear cells were stimulated in vitro with subtoxic concentrations of the strong haptens 5-chloro-2-methylisothiazolinone plus 2-methylisothiazolinone and 2, 4, 6-trinitrochlorobenzene, the thiol-reactive reagents N-hydroxymaleim…
Plasma membrane Ca2+ ATPase 4 is required for sperm motility and male fertility.
2004
Calcium and Ca(2+)-dependent signals play a crucial role in sperm motility and mammalian fertilization, but the molecules and mechanisms underlying these Ca(2+)-dependent pathways are incompletely understood. Here we show that homozygous male mice with a targeted gene deletion of isoform 4 of the plasma membrane calcium/calmodulin-dependent calcium ATPase (PMCA), which is highly enriched in the sperm tail, are infertile due to severely impaired sperm motility. Furthermore, the PMCA inhibitor 5-(and-6)-carboxyeosin diacetate succinimidyl ester reduced sperm motility in wild-type animals, thus mimicking the effects of PMCA4 deficiency on sperm motility and supporting the hypothesis of a pivot…
Naphthalimide imidazolium-based supramolecular hydrogels as bioimaging and theranostic soft materials
2020
1,8-Naphthalimide-based imidazolium salts differing for the alkyl chain length and the nature of the anion were synthesized and characterized to obtain fluorescent probes for bioimaging applications. First, their self-assembly behavior and gelling ability were investigated in water and water/dimethyl sulfoxide binary mixtures. Only salts having longer alkyl chains were able to give supramolecular hydrogels, whose properties were investigated by using a combined approach of fluorescence, resonance light scattering, and rheology measurements. Morphological information was obtained by scanning electron microscopy. In addition, conductive properties of organic salts in solution and gel state we…
Perylene Derivatives As Useful SERRS Reporters, Including Multiplexing Analysis
2015
Five perylene bisimide (PBI) derivatives were designed and synthesized, on the basis of quantum-chemical calculations. The influence of halogen substituents on the shape and energy of the frontier orbitals and the Raman spectra were calculated, in the prospect use in surface-enhanced resonance Raman scattering (SERRS) studies. The corresponding experiments confirmed a very strong SERRS response in the presence of pristine (i.e., uncoated) gold nanoparticles. These spectra can be used for multiplexing measurements, namely measurements in which, by using a single laser excitation, one can recognize the simultaneous presence of several analytes.