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The anomalous interaction between metal ions and the peptide beta-amyloid is one of the hallmarks of Alzheimer's disease. Metal-binding biopolymers, including polysaccharides, can elucidate the fundamental aspects of metal ions' interactions with biological tissue and their interplay in Alzheimer's disease. This work focuses on the role of the alginate composition on Cu(II) adsorption in the presence of histidine or β-amyloid, the peptide associated with the progression of Alzheimer's disease. Alginate samples with different mannuronic/guluronic (M/G) ratios led to similar Cu(II) adsorption capacities, following the Langmuir isotherm and the pseudo-second-order adsorption kinetic models. Although the presence of histidine produced up to a 20% reduction in the copper adsorption capacity in guluronic-rich alginate samples (M/G~0.61), they presented stable bidentate chelation of the metallic ion. Chemical analyses (FTIR and XPS) demonstrated the role of hydroxyl and carboxyl groups in copper ion chelation, whereas both crystallinity and morphology analyses indicated the prevalence of histidine interaction with guluronic-rich alginate. Similar results were observed for Cu(II) adsorption in alginate beads in the presence of beta-amyloid and histidine, suggesting that the alginate/histidine system is a simple yet representative model to probe the application of biopolymers to metal ion uptake in the presence of biological competitors.
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http://dx.doi.org/10.3390/molecules27238334 | DOI Listing |
Int J Biol Macromol
September 2025
Department of Chemical Sciences, Ariel University, 70400, Israel. Electronic address:
Doubly His-tagged mCherry red fluorescent proteins are observed to form fibers and sheets at neutral pH in the presence of no more than equimolar amounts of Zn or Ni. These architectures, on the order of 10 μm in extent, are detected with scanning transmission electron microscopy imaging. Far ultraviolet circular dichroism spectroscopy attests to the preservation of the native secondary structure of mCherry, while the emission spectrum reveals the maintenance of the chemical environment of the fluorophore site.
View Article and Find Full Text PDFAnal Chem
September 2025
Qilu University of Technology (Shandong Academy of Sciences), Shandong Analysis and Test Center, Jinan 250014, China.
Abnormal levels of trypsin in the human body can lead to various diseases, yet conventional detection methods often lack operational simplicity and real-time readout capabilities. This work presents a state-of-the-art metal organic framework (MOF) nanozyme-integrated liquid crystal (LC) sensor (MHN-LC sensor) and demonstrates the detection of trypsin as a proof of the concept. By rational engineering of the MOF-808 framework with Al and l-histidine coordination, a novel MOF nanozyme (MHis-NE) exhibiting exceptional acetylcholinesterase (AChE)-mimetic activity is successfully prepared.
View Article and Find Full Text PDFInt J Biol Macromol
August 2025
Bursa Uludag University, Faculty of Arts and Science, Department of Chemistry, 16059 Gorukle, Bursa, Turkey. Electronic address:
In this study, poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methyl ester-Cu) [PHMCu] nanoparticles were synthesized by emulsion polymerization and used as carriers for L-asparaginase (L-ASNase) immobilization. The nanoparticles were characterized using SEM-EDX, TEM, FTIR, Zeta potential analyses. The binding affinity of L-ASNase on metal-chelated polymeric nanoparticles was investigated via surface plasmon resonance (SPR) analysis.
View Article and Find Full Text PDFBiochim Biophys Acta Gen Subj
August 2025
Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.. Electronic address:
Photosynthetic organisms often rely on two-component regulatory system to adapt to environmental changes. This system is crucial for connecting external signals with the response mechanism by controlling gene expression, eventually allowing the organism to acclimatize to various stresses. Cyanobacteria, in particular, possess a large number of these two-component systems.
View Article and Find Full Text PDFMicroorganisms
August 2025
Research Center for Advanced Science and Technology, Division of Gene Research, Shinshu University, Ueda 386-8567, Nagano, Japan.
Curli fimbriae are a major component of biofilm formation in , and their expression is regulated by numerous transcription factors and small regulatory RNAs (sRNAs). The RcsD-RcsC-RcsB phosphorelay system, which is involved in the envelope stress response, plays a role in this regulation. In this study, we report that DNase-I footprinting analysis revealed that the response regulator RcsB interacts with the -31 to +53 region of the promoter region of , which encodes a major regulator of biofilm formation, and thus contributes to its transcriptional repression.
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