The interaction of caffein and myoglobin was investigated by fluorescence spectroscopy and synchronous fluorescence spectroscopy. The intrinsic fluorescence of myoglobin was significantly quenched by caffein under the physiological condition (pH 7.4). The results indicated that caffeine was capable of binding with myoglobin to form a 1:1 complex and the quenching mechanism of myoglobin affected by caffeine was shown to be a static quenching procedure by calculating quenching constant, binding sites and binding constant. According to the thermodynamic parameters, the main binding force of the interaction is electrostatic force and hydrophobic force. The change in the micro-circumstance of aminos of myoglobin was analyzed by synchronous fluorescence spectrometry. The result indicated that caffeine can change the conformation of the protein, leading to the change in the micro-environment of tryptophane and tyrosine residues from hydrophobic environment to hydrophilic environment to different extent.
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ACS Nano
January 2025
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.
Variance in the properties of optical mesoscopic probes is often a limiting factor in applications. In the thermodynamic limit, the smaller the probe, the larger the relative variance. However, specific viral protein cages can assemble efficiently outside the bounds of statistical fluctuations at equilibrium through a process that is characterized by intrinsic quality-control and self-limiting capabilities.
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December 2024
Stanford University, Stanford, CA, USA.
Background: Recent studies suggest that iron and neuroinflammation are key components of Alzheimer's Disease (AD) pathology. Ferrous Fe can cause oxidative stress and cellular toxicity, but it is unknown to what extent Fe is elevated in AD, in particular with the hippocampus. To answer this question, we quantified iron oxidation state in frozen human brain hippocampi.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
USC Keck School of Medicine, Los Angeles, CA, USA.
Background: Human Apolipoprotein (APOE) has three isoforms, ε2, ε3, and ε4 among which ε4 (APOE4) confers the highest risk for late-onset Alzheimer's disease (AD). APOE4 is also the most prone to aggregate among APOE isoforms. Current evidence strongly suggests that APOE aggregation leads to neuronal dysfunction and eventually to AD.
View Article and Find Full Text PDFAnal Methods
January 2025
Molecular Foundry Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
X-ray footprinting mass spectrometry (XFMS) is a structural biology method that uses broadband X-rays for hydroxyl radical labeling to map protein interactions and conformation in solution. However, while XFMS alone provides important structural information on biomolecules, as we move into the era of the interactome, hybrid methods are becoming increasingly necessary to gain a comprehensive understanding of protein complexes and interactions. Toward this end, we report the development of the first synergetic application of inline and real-time fluorescent spectroscopy at the Advanced Light Source's XFMS facility to study local protein interactions and global conformational changes simultaneously.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
February 2025
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russian Federation.
The crystal structures and hyperfine magnetic parameters of EuFe(BO) and mixed EuLaFe(BO) were studied over a wide temperature range in order to analyze correlations of the structural and magnetic features and the phase transitions in multiferroic compounds of the rare-earth iron borate family. The chemical compositions of the crystals are reported from X-ray fluorescence analysis. The crystal structures of EuFe(BO) and EuLaFe(BO) were determined using single-crystal X-ray diffraction in the temperature range 25-500 K.
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