Water Detoxification by a Substrate-Bound Catecholamine Adsorbent.
Ontology highlight
ABSTRACT:
SUBMITTER: Lee M
PROVIDER: S-EPMC3670806 | biostudies-literature | 2012 Nov
REPOSITORIES: biostudies-literature
Publications
Water Detoxification by a Substrate-Bound Catecholamine Adsorbent.
Lee Mihyun M Rho Junsung J Lee Dong-Eun DE Hong Seonki S Choi Sun-Ju SJ Messersmith Phillip B PB Lee Haeshin H
ChemPlusChem 20121101 11
Similar Datasets
Project description:Reactive carbonyl compounds (RCCs) such as hydroxynonenol, malondialdehyde, acrolein, crotonaldehyde, methylglyoxal, and glyoxal accumulate at higher levels under stress in plants and damage the cell metabolic activities. Plants have evolved several detoxifying enzymes such as aldo-keto reductases (AKRs), aldehyde/alcohol dehydrogenases (ALDH/ADH), and glyoxalases. We report the phylogenetic relationship of these proteins and in silico analysis of rice-detoxifying protein structures and their substrate affinity with cofactors using docking and molecular simulation studies. Molecular simulations with nicotinamide adenine dinucleotide phosphate or glutathione cofactor docking with commonly known reactive substrates suggests that the AKRs, ALDH, and ADH proteins attain maximum conformational changes, whereas glyoxalase has fewer conformational changes with cofactor binding. Several AKRs showed a significant binding affinity with many RCCs. The rice microarray studies showed enhanced expression of many AKRs in resistant genotypes, which also showed higher affinity to RCCs, signifying their importance in managing carbonyl stress. The higher expression of AKRs is regulated by stress-responsive transcription factors (TFs) as we identified stress-specific cis-elements in their promoters. The study reports the stress-responsive nature of AKRs, their regulatory TFs, and their best RCC targets, which may be used for crop improvement programs.
| S-EPMC7860239 | biostudies-literature
Project description:Lead halide perovskite (LHP) is a promising material for various optoelectronic applications. Surface coating on particles is a common strategy to improve their functionality and environmental stability, but LHP is not amenable to most coating chemistries because of its intrinsic weakness against polar solvents. Here, we describe a novel method of synthesizing LHP microlasers in a super-saturated polar solvent using sonochemistry and applying various functional coatings on individual microlasers in situ. We synthesize cesium lead bromine perovskite (CsPbBr3) microcrystals capped with organic poly-norepinephrine (pNE) layers. The catechol group of pNE coordinates to bromine-deficient lead atoms, forming a defect-passivating and diffusion-blocking shell. The pNE layer enhances the material lifetime of CsPbBr3 in water by 2,000-folds, enabling bright luminescence and lasing from single microcrystals in water. Furthermore, the pNE shell permits biofunctionalization with proteins, small molecules, and lipid bilayers. Luminescence from CsPbBr3 microcrystals is sustained in water over 1 hour and observed in live cells. The functionalization method may enable new applications of LHP laser particles in water-rich environments.
| S-EPMC8447242 | biostudies-literature
Project description:Hsp70 chaperones keep protein homeostasis facilitating the response of organisms to changes in external and internal conditions. Hsp70s have two domains-nucleotide binding domain (NBD) and substrate binding domain (SBD)-connected by a conserved hydrophobic linker. Functioning of Hsp70s depend on tightly regulated cycles of ATP hydrolysis allosterically coupled, often together with cochaperones, to the binding/release of peptide substrates. Here we describe the crystal structure of the Mycoplasma genitalium DnaK (MgDnaK) protein, an Hsp70 homolog, in the noncompact, nucleotide-bound/substrate-bound conformation. The MgDnaK structure resembles the one from the thermophilic eubacteria DnaK trapped in the same state. However, in MgDnaK the NBD and SBD domains remain close to each other despite the lack of direct interaction between them and with the linker contacting the two subdomains of SBD. These observations suggest that the structures might represent an intermediate of the protein where the conserved linker binds to the SBD to favor the noncompact state of the protein by stabilizing the SBDβ-SBDα subdomains interaction, promoting the capacity of the protein to sample different conformations, which is critical for proper functioning of the molecular chaperone allosteric mechanism. Comparison of the solved structures indicates that the NBD remains essentially invariant in presence or absence of nucleotide.
| S-EPMC5916121 | biostudies-literature
Project description:The efficient removal of trace carcinogenic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and ionic dyes, from water is an important technical challenge. We report a highly effective recyclable multifunctional azobenzene (AZ)-based silica-supported polymeric adsorbent which can simultaneously remove both PAHs and anionic dyes from water to below parts per billion (ppb) level based on multiple interactions such as the hydrophobic effect, π-π stacking and electrostatic interactions, thus providing a new strategy for designer water remediation materials.
| S-EPMC4650936 | biostudies-literature
Project description:Adsorption using magnetic adsorbents makes the phosphorus removal from water simple and efficient. However, most of the reported magnetic adsorbents use chemically synthesized nanoparticles as magnetic cores, which are expensive and environmentally unfriendly. Replacing the nanomagnetic cores by cheap and green magnetic materials is essential for the wide application of this technique. In this paper, coal-fly-ash magnetic spheres (MSs) were processed to produce a cheap and eco-friendly magnetic core. A magnetic adsorbent, ZrO2 coated ball-milled MS (BMS@ZrO2), was prepared through a simple chemical precipitation method. Careful structural investigations indicate that a multipore structural amorphous ZrO2 layer has grown on the MS core. The specific surface area of BMS@ZrO2 is 48 times larger than that of the MS core. The highest phosphorus adsorption is tested as 16.47 mg g-1 at pH = 2. The BMS@ZrO2 adsorbent has a saturation magnetization as high as 33.56 emu g-1, enabling efficient magnetic separation. Zeta potential measurements and X-ray photoelectron spectroscopy analysis reveal that the phosphorus adsorption of BMS@ZrO2 is triggered by the electrostatic attraction and the ligand exchange mechanism. The BMS@ZrO2 adsorbent could be reused several times after proper chemical treatment.
| S-EPMC7542858 | biostudies-literature
Project description:In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES) for removal of methylene blue (MB) dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption of cationic MB molecules. As an extra challenge, to augment the adsorbent's properties in terms of adsorption capacity in neutral and acidic conditions and thermal stability, vanadium pentoxide (V₂O₅) nanoparticles were added to the nanofibers. Adsorption data were analyzed according to the Freundlich adsorption model. The thermodynamic parameters verified that only at basic pH is the adsorption spontaneous and in general the process is entropy-driven and endothermic. The kinetics of the adsorption process was evaluated by the pseudo-first- and pseudo-second-order models. The latter model exhibited the highest correlation with data. In sum, the adsorbent showed a promising potential for dye removal from industrial dyeing wastewater systems, especially when envisaging their alkaline and hot conditions.
| S-EPMC5456603 | biostudies-other
Project description:In spite of great progress in resolving the geometric structure of the water-splitting Mn(4)O(x)Ca cluster in photosystem II, the binding sites and modes of the two substrate water molecules are still insufficiently characterized. While time-resolved membrane-inlet mass spectrometry measurements indicate that both substrate water molecules are bound to the oxygen-evolving complex (OEC) in the S(2) and S(3) states (Hendry and Wydrzynski in Biochemistry 41:13328-13334, 2002), it is not known (1) if they are both Mn-bound, (2) if they are terminal or bridging ligands, and (3) in what protonation state they are bound in the different oxidation states S(i) (i = 0, 1, 2, 3, 4) of the OEC. By employing (17)O hyperfine sublevel correlation (HYSCORE) spectroscopy we recently demonstrated that in the S(2) state there is only one (type of) Mn-bound oxygen that is water exchangeable. We therefore tentatively identified this oxygen as one substrate 'water' molecule, and on the basis of the finding that it has a hyperfine interaction of about 10 MHz with the electron spin of the Mn(4)O(x)Ca cluster, we suggest that it is bound as a Mn-O-Mn bridge within a bis-mu(2) oxo-bridged unit (Su et al. in J Am Chem Soc 130:786-787, 2008). Employing pulse electron paramagnetic resonance, (1)H/(2)H Mims electron-nuclear double resonance and (2)H-HYSCORE spectroscopies together with (1)H/(2)H-exchange here, we test this hypothesis by probing the protonation state of this exchangeable oxygen. We conclude that this oxygen is fully deprotonated. This result is discussed in the light of earlier reports in the literature.
| S-EPMC2784071 | biostudies-other
Project description:Recently, pharmaceutical pollutants in water have emerged as a global concern as they give threat to human health and the environment. In this study, graphene nanoplatelets (GNPs) were used to efficiently remove antibiotics sulfamethoxazole (SMX) and analgesic acetaminophen (ACM) as pharmaceutical pollutants from water by an adsorption process. GNPs; C750, C300, M15 and M5 were characterized by high-resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction and Brunauer-Emmett-Teller. The effects of several parameters viz. solution pH, adsorbent amount, initial concentration and contact time were studied. The parameters were optimized by a batch adsorption process and the maximum removal efficiency for both pharmaceuticals was 99%. The adsorption kinetics and isotherms models were employed, and the experimental data were best analysed with pseudo-second kinetic and Langmuir isotherm with maximum adsorption capacity (Qm) of 210.08 mg g-1 for SMX and 56.21 mg g-1 for ACM. A regeneration study was applied using different eluents; 5% ethanol-deionized water 0.005 M NaOH and HCl. GNP C300 was able to remove most of both pollutants from environmental water samples. Molecular docking was used to simulate the adsorption mechanism of GNP C300 towards SMX and ACM with a free binding energy of -7.54 kcal mol-1 and -5.29 kcal mol-1, respectively, which revealed adsorption occurred spontaneously.
| S-EPMC7890490 | biostudies-literature
Project description:Multidrug ABC transporters translocate drugs across membranes by a mechanism for which the molecular features of drug release are so far unknown. Here, we resolved three ATP-Mg2+-bound outward-facing conformations of the Bacillus subtilis (homodimeric) BmrA by x-ray crystallography and single-particle cryo-electron microscopy (EM) in detergent solution, one of them with rhodamine 6G (R6G), a substrate exported by BmrA when overexpressed in B. subtilis. Two R6G molecules bind to the drug-binding cavity at the level of the outer leaflet, between transmembrane (TM) helices 1-2 of one monomer and TM5'-6' of the other. They induce a rearrangement of TM1-2, highlighting a local flexibility that we confirmed by hydrogen/deuterium exchange and molecular dynamics simulations. In the absence of R6G, simulations show a fast postrelease occlusion of the cavity driven by hydrophobicity, while when present, R6G can move within the cavity, maintaining it open.
| S-EPMC8791611 | biostudies-literature
Project description:The hydrogen bonding of ligated water in ferric, high-spin, resting-state substrate complexes of heme oxygenase from Neisseria meningitidis has been systematically perturbed by variable electron-withdrawing substituents on the hemin periphery. The pattern of 1H NMR-detected dipolar shifts due to the paramagnetic anisotropy is strongly conserved among the four complexes, with the magnitude of dipolar shifts or anisotropy increasing in the order of substituent formyl < vinyl < methyl. The magnetic anisotropy is axial and oriented by the axial Fe-His23 bond, and while individual anisotropies have uncertainties of approximately 5%, the relative values of deltachi (and the zero-field splitting constant, D proportional, variant deltachi(ax)) are defined to 1%. The unique changes in the axial field strength implied by the variable zero-field splitting are in accord with expectations for the axial water serving as a stronger H-bond donor in the order of hemin substituents formyl > vinyl > methyl. These results establish the axial anisotropy (and D) as a sensitive probe of the H-bonding properties of a ligated water in resting-state, substrate complexes of heme oxygenase. Correction of observed labile proton chemical shifts for paramagnetic influences indicates that Gln49 and His53, some approximately 10 angstroms from the iron, sense the change in the ligated water H-bonding to the three nonligated ordered water molecules that link the two side chains to the iron ligand. The present results augur well for detecting and characterizing changes in distal water H-bonding upon mutagenesis of residues in the distal network of ordered water molecules and strong H-bonds.
| S-EPMC2566965 | biostudies-literature