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Fumarase catalyzes the reversible, stereospecific hydration/dehydration of fumarate to L-malate during the Kreb's cycle. In the crystal structure of the tetrameric fumarase, it was found that some of the active site residues S145, T147, N188 G364 and H235 had water-mediated hydrogen bonding interactions with pyromellitic acid and citrate which help to the protonation state for the conversion of fumarate to malate. When His 235 is mutated with Asn (H235N), water-mediated interactions were lost due to the shifting of active site water molecule by 0.7 Å away. Molecular dynamics (MD) simulations were also carried out by NAMD and analyzed using Assisted Model Building with Energy Refinement (AMBER) program to better understand the conformational stability and other aspects during the binding of pyromellitic acid and citrate with native and mutant FH. The role of hydrogen bonds and hydrophobic interactions was also analyzed. The present study confirms that the H235N mutation has a major effect on the catalytic activity of fumarase which is evident from the biochemical studies.
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http://dx.doi.org/10.1142/S0219720017500263 | DOI Listing |
ACS Appl Mater Interfaces
July 2025
School of Physics and Materials Science, Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China.
The high cost and low reproducibility issues of Si as the anode material for lithium-ion batteries still need to be addressed. Herein, we present a facile and scalable bead-grinding technique to down-size the cheap micron-Si into Si nanoflakes with in situ bonded pyromellitic acid (PMA) molecules. The bonded PMA not only deactivates the surfaces of Si nanoflakes but also acts as an artificial solid-electrolyte interface film.
View Article and Find Full Text PDFEnviron Res
October 2025
School of Engineering and Built Environment, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia. Electronic address:
This study presents a performance-driven selection of green metal-organic frameworks (MOFs), integrating yield, cost-effectiveness, and adsorption efficiency, critical yet often overlooked criteria in MOF development. The selected MOFs were synthesized using environmentally benign solvents, ethanol (EtOH) and deionized water (DIW), under mild temperature conditions, offering a scalable and sustainable route. Three zirconium-based green MOFs were identified: one Terephthalic acid (TPA)-based (GR2-MOF(80)) and two Pyromellitic acid (PMA)-based (GR8-MOF(25) and GR10-MOF(25)).
View Article and Find Full Text PDFPolymers (Basel)
May 2025
Branch of Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of National Research Centre «Kurchatov Institute»-Institute of Macromolecular Compounds, Bolshoi, Pr. 31 (V.O.), 199004 St. Petersburg, Russia.
Polyimides (PIs) are materials that are resistant to high temperatures and crucial for the manufacturing of films, fibers, coatings, and 3D-printed items. PIs are widely used as electrically insulating materials in electronics and electrical engineering. This study investigated how the chemical structure (i.
View Article and Find Full Text PDFDalton Trans
May 2025
Chemistry Department, College of Science, King Saud University, P. O. Box 2455, Riyadh-11451, Saudi Arabia.
Metal-organic frameworks (MOFs) have emerged as promising materials for supercapacitor applications; however, challenges such as limited conductivity, stability, and rate capability hinder their practical implementation. Despite extensive efforts, including hybridization and bimetallic strategies, a significant performance gap remains. In this work, we introduce a drive towards a bi-linker approach to engineer nickel-based MOFs, systematically varying the ratio of pyridine-2,6-dicarboxylic acid and pyromellitic acid (linkers) to tailor their morphological evolution and electrochemical properties.
View Article and Find Full Text PDFJ Colloid Interface Sci
August 2025
School of Materials Science and Engineering, University of Jinan, Jinan, Shandong 250022, China. Electronic address:
Red-emitting carbon dots (R-CDs), a novel class of environmentally benign, non-toxic, and pollution-free nanomaterials, have garnered considerable attention in the field of solid-state white light-emitting diodes (WLEDs) owing to their exceptional optical properties. Herein, we synthesized R-CDs-1 with a 671 nm emission using a simple solvent thermal method employing pyromellitic acid and 1,8-diaminonaphthalene as precursors. Structural characterization and density functional theory (DFT) simulations were employed to demonstrate that the reduction in the bandgap due to structural changes leads to a redshift in the emission spectrum of R-CDs-1.
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