DNA binding and unwinding by self-assembled supramolecular hetero-bimetallacycles.
Ontology highlight
ABSTRACT:
SUBMITTER: Mishra A
PROVIDER: S-EPMC3237687 | biostudies-literature | 2011 Nov
REPOSITORIES: biostudies-literature
Publications
DNA binding and unwinding by self-assembled supramolecular hetero-bimetallacycles.
Mishra Anurag A Ravikumar Sambandam S Hong Soon Ho SH Kim Hyunuk H Vajpayee Vaishali V Lee Hyewoo H Ahn Byungchan B Wang Ming M Stang Peter J PJ Chi Ki-Whan KW
Organometallics 20111101 23
Two new tetracationic hetero-bimetallacycles were prepared from a bis-pyridine amide ligand and metal (Pd and Pt) acceptors. We found that both self-assembled hetero-bimetallacycles bind and unwind supercoiled DNA as established by photophysical and gel electrophoresis analyses, respectively. ...[more]
Similar Datasets
Project description:Two new tetracationic hetero-bimetallacycles, compounds 4 and 5, have been constructed from an N,N'-bis(4-(pyridin-4-ylethynyl)phenyl)pyridine-2,6-dicarboxamide ligand (1), and cis-blocked complexes [M(dppf)(OTf)2 ] (dppf=1,1'-bis(diphenylphosphino)ferrocene; OTf=trifluoromethanesulfonate; M=Pd (2), Pt (3)) in CH3 NO2 /CH2 Cl2 (1:1) solvent. Both complexes were isolated with adequate yields as triflate salts and were then characterized using (1) H, (13) C, and (31) P?NMR spectroscopy, elemental analysis, UV/Vis spectroscopy, and high-resolution electrospray mass spectrometry (HR-ESMS). The molecular structure of 4 was determined by molecular mechanics force-field calculations. The cytotoxic effect of both new complexes were analyzed against T98G (brain tumor), KB (head and neck cancer), SNU-80 (thyroid cancer), and HEK-293 non-malignant cell lines. The cytotoxicity of complexes 4 and 5 were found to be considerably more effective against cancer cells than reference drug cisplatin. Annexin-V/PI staining, caspase-3/7 activity, and the reduction in mitochondrial membrane potential justify a significant level of apoptosis in complex-treated cells.
| S-EPMC5796531 | biostudies-literature
Project description:Supramolecular nanogels are an emerging class of polymer nanocarriers for intracellular delivery, due to their straightforward preparation, biocompatibility, and capability to spontaneously encapsulate biologically active components such as DNA. A completely biodegradable three-component cationic supramolecular nanogel was designed exploiting the multivalent host-guest interaction of cyclodextrin and adamantane attached to a polypeptide backbone. While cyclodextrin was conjugated to linear poly-L-lysine, adamantane was grafted to linear as well as star shaped poly-L-lysine. Size control of nanogels was obtained with the increase in the length of the host and guest polymer. Moreover, smaller nanogels were obtained using the star shaped polymers because of the compact nature of star polymers compared to linear polymers. Nanogels were loaded with anionic model cargoes, pyranine and carboxyfluorescein, and their enzyme responsive release was studied using protease trypsin. Confocal microscopy revealed successful transfection of mammalian HeLa cells and intracellular release of pyranine and plasmid DNA, as quantified using a luciferase assay, showing that supramolecular polypeptide nanogels have significant potential in gene therapy applications.
| S-EPMC8457085 | biostudies-literature
Project description:Complex morphologies, as is the case in self-assembled fibrillar networks (SAFiNs) of 1,3:2,4-Dibenzylidene sorbitol (DBS), are often characterized by their Fractal dimension and not Euclidean. Self-similarity presents for DBS-polyethylene glycol (PEG) SAFiNs in the Cayley Tree branching pattern, similar box-counting fractal dimensions across length scales, and fractals derived from the Avrami model. Irrespective of the crystallization temperature, fractal values corresponded to limited diffusion aggregation and not ballistic particle-cluster aggregation. Additionally, the fractal dimension of the SAFiN was affected more by changes in solvent viscosity (e.g., PEG200 compared to PEG600) than crystallization temperature. Most surprising was the evidence of Cayley branching not only for the radial fibers within the spherulitic but also on the fiber surfaces.
| S-EPMC8167784 | biostudies-literature
Project description:An important goal of nanotechnology is to assemble multiple molecules while controlling the spacing between them. Of particular interest is the phenomenon of multivalency, which is characterized by simultaneous binding of multiple ligands on one biological entity to multiple receptors on another. Various approaches have been developed to engineer multivalency by linking multiple ligands together. However, the effects of well-controlled inter-ligand distances on multivalency are less well understood. Recent progress in self-assembling DNA nanostructures with spatial and sequence addressability has made deterministic positioning of different molecular species possible. Here we show that distance-dependent multivalent binding effects can be systematically investigated by incorporating multiple-affinity ligands into DNA nanostructures with precise nanometre spatial control. Using atomic force microscopy, we demonstrate direct visualization of high-affinity bivalent ligands being used as pincers to capture and display protein molecules on a nanoarray. These results illustrate the potential of using designer DNA nanoscaffolds to engineer more complex and interactive biomolecular networks.
| S-EPMC2556356 | biostudies-literature
Project description:Nature employs self-assembly to fabricate the most complex molecularly precise machinery known to man. Heteromolecular, two-dimensional self-assembled networks provide a route to spatially organize different building blocks relative to each other, enabling synthetic molecularly precise fabrication. Here we demonstrate optoelectronic function in a near-to-monolayer molecular architecture approaching atomically defined spatial disposition of all components. The active layer consists of a self-assembled terrylene-based dye, forming a bicomponent supramolecular network with melamine. The assembly at the graphene-diamond interface shows an absorption maximum at 740?nm whereby the photoresponse can be measured with a gallium counter electrode. We find photocurrents of 0.5?nA and open-circuit voltages of 270?mV employing 19?mW?cm(-2) irradiation intensities at 710?nm. With an ex situ calculated contact area of 9.9 × 10(2)??m(2), an incident photon to current efficiency of 0.6% at 710?nm is estimated, opening up intriguing possibilities in bottom-up optoelectronic device fabrication with molecular resolution.
| S-EPMC4773422 | biostudies-literature
Project description:Inspired by biological systems, we report a supramolecular polymer-colloidal hydrogel (SPCH) composed of 98 wt % water that can be readily drawn into uniform ([Formula: see text]6-[Formula: see text]m thick) "supramolecular fibers" at room temperature. Functionalized polymer-grafted silica nanoparticles, a semicrystalline hydroxyethyl cellulose derivative, and cucurbit[8]uril undergo aqueous self-assembly at multiple length scales to form the SPCH facilitated by host-guest interactions at the molecular level and nanofibril formation at colloidal-length scale. The fibers exhibit a unique combination of stiffness and high damping capacity (60-70%), the latter exceeding that of even biological silks and cellulose-based viscose rayon. The remarkable damping performance of the hierarchically structured fibers is proposed to arise from the complex combination and interactions of "hard" and "soft" phases within the SPCH and its constituents. SPCH represents a class of hybrid supramolecular composites, opening a window into fiber technology through low-energy manufacturing.
| S-EPMC5547633 | biostudies-literature
Project description: Not available
| S-EPMC3088165 | biostudies-literature
Project description:Polysaccharides present in the glycocalyx and extracellular matrix are highly important for a multitude of functions. Oligo- and polysaccharides-based biomaterials are being developed to mimic the glycocalyx, but the spatial functionalization of these polysaccharides represents a major challenge. In this paper, a series of benzene-1,3,5-tricarboxamide (BTA) based supramolecular monomers is designed and synthesized with mono- (BTA-?-d-glucose; BTA-Glc and BTA-?-d-mannose; BTA-Man) or disaccharides (BTA-?-d-cellobiose; BTA-Cel) at their periphery or a monosaccharide (BTA-OEG4-?-d-mannose; BTA-OEG4-Man) at the end of a tetraethylene glycol linker. These glycosylated BTAs have been used to generate supramolecular assemblies and it is shown that the nature of the carbohydrate appendage is crucial for the supramolecular (co)polymerization behavior. BTA-Glc and BTA-Man are shown to assemble into micrometers long 1D (bundled) fibers with opposite helicities, whereas BTA-Cel and BTA-OEG4-Man formed small spherical micelles. The latter two monomers are used in a copolymerization approach with BTA-Glc, BTA-Man, or ethylene glycol BTA (BTA-OEG4) to give 1D fibers with BTA-Cel or BTA-OEG4-Man incorporated. Consequently, the carbohydrate appendage influences both the assembly behavior and the internal order. Using this approach it is possible to create 1D-fibers with adjustable saccharide densities exhibiting tailored dynamic exchange profiles. Furthermore, hydrogels with tunable mechanical properties can be achieved, opening up possibilities for the development of multicomponent functional biomaterials.
| S-EPMC6733156 | biostudies-literature
Project description:Since the approval of imatinib in 2001, kinase inhibitors have revolutionized cancer therapies. Inside this family of phosphotransferases, casein kinase 2 (CK2) is of great interest and numerous scaffolds have been investigated to design CK2 inhibitors. Recently, functionalized indeno[1,2-b]indoles have been revealed to have high potency against human cancer cell lines such as MCF-7 breast carcinoma and A-427 lung carcinoma. 4-Methoxy-5-isopropyl-5,6,7,8-tetrahydroindeno[1,2-b]indole-9,10-dione (THN7), identified as a potent inhibitor of CK2 (IC50 = 71 nM), was selected for an encapsulation study in order to evaluate its antiproliferative activity as THN7-loaded cyclodextrin nanoparticles. Four ?-cyclodextrins (?-CDs) were selected to encapsulate THN7 and all experiments indicated that the nanoencapsulation of this CK2 inhibitor in ?-CDs was successful. No additional surface-active agent was used during the nanoformulation process. Nanoparticles formed between THN7 and ?-C?H13 amphiphilic derivative gave the best results in terms of encapsulation rate (% of associated drug = 35%), with a stability constant (K11) of 298 mol·L-1 and a size of 132 nm. Hemolytic activity of the four ?-CDs was determined before the in cellulo evaluation and the ?-C?H13 derivative gave the lowest value of hemolytic potency (HC50 = 1.93 mol·L-1). Only the THN7-loaded cyclodextrin nanoparticles showing less toxicity on human erythrocytes (?-C?H13, ?-C?H17 and ?-C?H?) were tested against A-427 cells. All drug-loaded nanoparticles caused more cytotoxicity against A-427 cells than THN7 alone. Based on these results, the use of amphiphilic CD nanoparticles could be considered as a drug delivery system for indeno[1,2-b]indoles, allowing an optimized bioavailability and offering perspectives for the in vivo development of CK2 inhibitors.
| S-EPMC5874706 | biostudies-literature
Project description:Supramolecular chemistry has been employed to develop flexible and adaptable multivalent neoglycoconjugates for binding galectin-1 (Gal-1). Gal-1, a dimeric lectin with two galactoside-binding sites, regulates cancer progression and immune responses. Self-assembled pseudopolyrotaxanes consisting of lactoside-displaying cyclodextrin (LCD) "beads" threaded onto polyviologen "strings" display mobile ligands as a result of cyclodextrin rotation about, and limited translation along, the polymer chain. The pseudopolyrotaxanes rapidly and efficiently precipitate Gal-1 and provide valency-corrected enhancements of up to 30-fold compared to native lactose and 20-fold over free LCD in a T-cell agglutination assay. A supramolecular statistical effect was observed, wherein the efficacy of Gal-1 inhibition correlates with the number of ligands connected to each other solely through mechanical and noncovalent interactions. Such flexible and adaptable self-assembled pseudopolyrotaxanes show promise for the study of multivalent interactions and targeting of therapeutically relevant lectins.
| S-EPMC2072908 | biostudies-literature