Amino Acid-Viologen Hybrids: Synthesis, Cucurbituril Host-Guest Chemistry, and Implementation on the Production of Peptides.
Ontology highlight
ABSTRACT:
SUBMITTER: Barravecchia L
PROVIDER: S-EPMC8749954 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:This study describes the influence of selected synthetic macrocycle on the gene expression in Pseudomonas aeruginosa PAO1. In this work, we propose two distinct functionalities responsible for a dual mechanism of action. We identified a water-soluble pillararene whose inner cavity tightly binds to specific homoserine lactones (HSLs) thereby interfering with interbacterial signalling, leading to effective synchronized suppression of exotoxins and biofilms in P. aeruginosa. An additional concerted mechanism of action is suggested that involves the cationic functional side groups on the pillararene that disrupt both the bacterial outer membrane and biofilms, to increase the penetration and efficacy of intracellular antibiotics.
2023-02-27 | GSE182853 | GEO
Project description:Pretargeted positron emission tomography is a macromolecule-driven nuclear medicine technique that involves targeting a preadministered antigen target-bound macromolecule with a radioligand in vivo, aiming to minimize the overall radiation dose. This study investigates the use of antibody based host-guest chemistry methodology for pretargeted positron emission tomography. We hypothesize that the novel pretargeting approach reported here overcomes the challenges the current pretargeting platforms have with the in vivo stability and modularity of the pretargeting components. A cucurbit[7]uril host molecule modified, anti-carcinoembryonic antigen antibody (M5A; CB7-M5A) and a 68Ga-radiolabeled ferrocene guest radioligand ([68Ga]Ga-NOTA-PEG3-NMe2-Fc) were studied as potential host-guest chemistry pretargeting agents for positron emission tomography in BxPC3 xenografted nude mice. The viability of the platform was studied via in vivo biodistribution and positron emission tomography. Tumor uptake of [68Ga]Ga-NOTA-PEG3-NMe2-Fc was significantly higher in mice which received CB7-M5A prior to the radioligand injection (pretargeted) (3.3 ± 0.7%ID/g) compared to mice which only received the radioligand (nonpretargeted) (0.2 ± 0.1%ID/g).
| S-EPMC9153067 | biostudies-literature
Project description: Not available
| S-EPMC2908483 | biostudies-literature
Project description:Two supramolecular complexes were prepared using cucurbiturils [CBs] as mediators and a four-armed p-xylene derivative (M1) as a guest molecule. The single crystals of these two complexes were obtained and successfully analyzed by single-crystal X-ray diffraction (SCXRD). An unexpected and intriguing 1 : 2 self-assembly arrangement between M1 and CB[8] was notably uncovered, marking its first observation. These host-guest complexes exhibit distinctive photophysical properties, especially emission behaviors. Invaluable insights can be derived from these single-crystal structures. The precious single-crystal structures provide both precise structural information regarding the supramolecular complexes and a deeper understanding of the intricate mechanisms governing their photophysical properties.
| S-EPMC10762720 | biostudies-literature
Project description:Our study showed that selected pillararene was able to decrease the level of cell death and demage caused to human A549 epithelial cells by Pseudomonas aeruginosa PAO1 infection. To further understand the protective effects of pillararene during bacterial infections, we analyzed total mRNA isolated from the A549 epithelial cells. Our study showed that pillararene alone had minimal effect on A549 epithelial cells. The addition of PAO1 to A549 cells greatly altered expression levels. The addition of pillararene to infected A549 epithelial cells displayed a concentration-dependent reduction in the inflammatory response.
2023-02-27 | GSE182847 | GEO
Project description:Prolonged retention of internalized nanoparticulate systems inside cells improves their efficacy in imaging, drug delivery, and theranostic applications. Especially, regulating exocytosis of the nanoparticles is a key factor in the fabrication of effective nanocarriers for chemotherapeutic treatments but orthogonal control of exocytosis in the cellular environment is a major challenge. Herein, we present the first example of regulating exocytosis of gold nanoparticles (AuNPs), a model drug carrier, by using a simple host-guest supramolecular system. AuNPs featuring quaternary amine head groups were internalized into the cells through endocytosis. Subsequent in situ treatment of a complementary cucurbit[7]uril (CB[7]) to the amine head groups resulted in the AuNP-CB[7] complexation inside cells, rendering particle assembly. This complexation induced larger particle assemblies that remained sequestered in the endosomes, inhibiting exocytosis of the particles without any observed cytotoxicity.
| S-EPMC4323993 | biostudies-literature
Project description:We investigated Xe binding in a previously reported paramagnetic metal-organic tetrahedral capsule, [Co4L6]4-, where L2- = 4,4'-bis[(2-pyridinylmethylene)amino][1,1'-biphenyl]-2,2'-disulfonate. The Xe-inclusion complex, [XeCo4L6]4-, was confirmed by 1H NMR spectroscopy to be the dominant species in aqueous solution saturated with Xe gas. The measured Xe dissociation rate in [XeCo4L6]4-, koff = 4.45(5) × 102 s-1, was at least 40 times greater than that in the analogous [XeFe4L6]4- complex, highlighting the capability of metal-ligand interactions to tune the capsule size and guest permeability. The rapid exchange of 129Xe nuclei in [XeCo4L6]4- produced significant hyperpolarized 129Xe chemical exchange saturation transfer (hyper-CEST) NMR signal at 298 K, detected at a concentration of [XeCo4L6]4- as low as 100 pM, with presaturation at -89 ppm, which was referenced to solvated 129Xe in H2O. The saturation offset was highly temperature-dependent with a slope of -0.41(3) ppm/K, which is attributed to hyperfine interactions between the encapsulated 129Xe nucleus and electron spins on the four CoII centers. As such, [XeCo4L6]4- represents the first example of a paramagnetic hyper-CEST (paraHYPERCEST) sensor. Remarkably, the hyper-CEST 129Xe NMR resonance for [XeCo4L6]4- (δ = -89 ppm) was shifted 105 ppm upfield from the diamagnetic analogue [XeFe4L6]4- (δ = +16 ppm). The Xe inclusion complex was further characterized in the crystal structure of (C(NH2)3)4[Xe0.7Co4L6]·75 H2O (1). Hydrogen bonding between capsule-linker sulfonate groups and exogenous guanidinium cations, (C(NH2)3)+, stabilized capsule-capsule interactions in the solid state and also assisted in trapping a Xe atom (∼42 Å3) in the large (135 Å3) cavity of 1. Magnetic susceptibility measurements confirmed the presence of four noninteracting, magnetically anisotropic high-spin CoII centers in 1. Furthermore, [Co4L6]4- was found to be stable toward aggregation and oxidation, and the CEST performance of [XeCo4L6]4- was unaffected by biological macromolecules in H2O. These results recommend metal-organic capsules for fundamental investigations of Xe host-guest chemistry as well as applications with highly sensitive 129Xe-based sensors.
| S-EPMC7672707 | biostudies-literature
Project description:Dynamic regulation of chemical reactivity is important in many complex chemical reaction networks, such as cascade reactions and signal transduction processes. Signal responsive catalysts could play a crucial role in regulating these reaction pathways. Recently, supramolecular encapsulation was reported to regulate the activities of artificial catalysts. We present a host-guest chemistry strategy to modulate the activity of commercially available synthetic organocatalysts. The molecular container cucurbit[7]uril was successfully applied to change the activity of four different organocatalysts and one initiator, enabling up- or down-regulation of the reaction rates of four different classes of chemical reactions. In most cases CB[7] encapsulation results in catalyst inhibition, however in one case catalyst activation by binding to CB[7] was observed. The mechanism behind this unexpected behavior was explored by NMR binding studies and pKa measurements. The catalytic activity can be instantaneously switched during operation, by addition of either supramolecular host or competitive binding molecules, and the reaction rate can be predicted with a kinetic model. Overall, this signal responsive system proves a promising tool to control catalytic activity.
| S-EPMC8251865 | biostudies-literature
Project description:We study the molecular dynamics and structures of the guest-host complexes of cucurbituril, CB[7], with spin probes through the conventional electron spin resonance (ESR), saturation transfer ESR (STESR), density functional theory (DFT), and molecular dynamics (MD) computations. Protonated TEMPOamine (I), a derivative of TEMPO having a positive charge and an octyl group on the quaternary nitrogen atom (II), and the neutral spin-labeled indole (III) are used as guests. To eliminate the overall complex rotation, the solutions of complexes in a solid CB[7] matrix were prepared. Resultantly, for all of the spin probes, the combined study of the conventional ESR and STESR spectra indicates the librational character of the rotational motion within the CB[7] cavity as opposed to the diffusional rotation over the whole solid angle. The kinetic accessibilities of the reporter NO groups to the paramagnetic complexes in aqueous solutions, determined by Heisenberg exchange broadening of the ESR spectra, together with the environment polarities from the hyperfine interaction values, as well as DFT computation results and MD simulations, were used to estimate the spin probe location relative to CB[7]. Utilizing the concept of the aqueous clusters surrounding the spin probes and CB[7] molecules and MD simulations has allowed the application of DFT to estimate the aqueous environment effects on the complexation energy and spatial structure of the guest-host complexes.
| S-EPMC7271031 | biostudies-literature
Project description:Two dansyl-modified ?-cyclodextrin derivatives (1 and 2) have been synthesized as host-guest sensory systems for the direct fluorescent detection of the peroxide explosives diacetone diperoxide (DADP) and triacetone triperoxide (TATP) in aqueous media. The sensing is based on the displacement of the dansyl moiety from the cavity of the cyclodextrin by the peroxide guest resulting in a decrease of the intensity of the fluorescence of the dye. Both systems showed similar fluorescent responses and were more sensitive towards TATP than DADP.
| S-EPMC5936911 | biostudies-literature