In this study, we performed differential scanning calorimetry (DSC) and pressure perturbation calorimetry (PPC) analysis of the thermal transition of cytochrome c from an acidic molten globule (MG) state with the protein concentrations of 0.5-18.2 mg/mL. DSC profiles were highly reversible and showed clear protein-concentration dependence, indicating that reversible oligomerization occurred accompanying the thermal transition from the MG state. The DSC and PPC data required at least a six-state model (MG1 ⇄ MG2 ⇄ D ⇄ / I ⇄ / I ⇄ / I) including three new oligomeric states: dimer (I), trimer (I), and tetramer (I) in addition to the three monomeric states previously characterized. Dynamic light scattering confirmed the oligomerization during the thermal transition. The partial specific volumes of these oligomeric states were found to be smaller than those of the monomeric states, MG2 and D, indicating dehydration of hydrophobic surface or hydration of released anions may occur with the reversible oligomerization.
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http://dx.doi.org/10.1021/acs.biochem.6b01225 | DOI Listing |
Nat Commun
January 2025
Institute for Materials Science, University of Stuttgart, D-70569, Stuttgart, Germany.
The knowledge of diffusion mechanisms in materials is crucial for predicting their high-temperature performance and stability, yet accurately capturing the underlying physics like thermal effects remains challenging. In particular, the origin of the experimentally observed non-Arrhenius diffusion behavior has remained elusive, largely due to the lack of effective computational tools. Here we propose an efficient ab initio framework to compute the Gibbs energy of the transition state in vacancy-mediated diffusion including the relevant thermal excitations at the density-functional-theory level.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Chemical and Petroleum Engineering Department, College of Engineering, United Arab Emirates University, PO Box 15551, Al Ain, United Arab Emirates. Electronic address:
In this study, the role of a transition metal complex in improving hydrolysis efficiency during nanocellulose production was analysed. Cellulose nanocrystals (CNCs) were extracted from date seeds by incorporating a copper metal complex during HCl hydrolysis. In contrast to traditional HCl hydrolysis at moderate conditions, which yielded only microcrystalline cellulose (MCC), this approach resulted in the extraction of CNCs with a 10 % improved yield compared to MCC.
View Article and Find Full Text PDFAppl Radiat Isot
December 2024
Department of Metallurgy and Materials Engineering, Faculty of Engineering and Natural Sciences, Konya Technical University, Konya, Turkey.
The EuDyGeO, EuLaGeO and EuHoGeO powder were obtained through a solid-state reaction method via multistep firing of stoichiometric ratios of EuO, GeO, DyO, LaO and HoO in open atmosphere at temperatures from 800 to 1150 °C. The thermal behaviour, phase formation, SEM/EDX analysis, photoluminescence properties, Curie tempereture, dielectric and piezoelectric properties of the samples were investigated by TG/DTA, XRD, SEM, PL, TG/DTA, LCR-meter and d-meter, respectively. The germenates having triclinic crystal system have D→F, D→F, D→F, D→F transitions of Eu ions.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA.
A key objective in nuclear and high-energy physics is to describe nonequilibrium dynamics of matter, e.g., in the early Universe and in particle colliders, starting from the standard model of particle physics.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Carlos III University of Madrid, Thermal and Fluids Engineering Department, Avenida de la Universidad, 30 (Sabatini building), 28911 Leganés (Madrid), Spain.
We present a surface analog to a dripping faucet, where a viscous liquid slides down an immiscible meniscus. Periodic pinch-off of the dripping filament is observed, generating a succession of monodisperse floating lenses. We show that this interfacial dripping faucet can be described analogously to its single-phase counterpart, replacing surface tension by the spreading coefficient, and even undergoes a transition to a jetting regime.
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