Journal of Physical Chemistry B
Papers 43239
1 page of 4,324 pages (43.2k results)
The Good-Karali theory is extended to simulate composite CD through a cholesteric stack by incorporating chromophore’s selective absorption and cholesteric stack’s selective reflection. Based on the independently evaluated anisotropic refractive indices and absorption coefficients, helical sense and pitch length, and film thickness, the theory is capable of describing transmission, reflection, and absorption through spin-cast cholesteric glassy liquid crystal films of a nonafluorene. The resulti...
Quantitative information of hydrogen bonding is crucial to our understanding of the structure and properties of associated liquids. Here we outline a simple procedure to establish the geometry of hydrogen bonds in liquid ethanol using proton NMR spectroscopy. We do so by exploiting differences in proton chemical shift values, that originate from the secondary isotope effect, to distinguish the methyl and hydroxyl group protons of CH3CH2OH and from those of the deuterated CH3CD2OH in the 1H NMR s...
Cells employ membrane-embedded antiporter proteins to control their pH, salt concentration, and volume. The large family of cation/proton antiporters is dominated by Na+/H+ antiporters that exchange sodium ions against protons, but homologous K+/H+ exchangers have recently been characterized. We show experimentally that the electroneutral NhaP1 of Methanocaldococcus jannaschii (MjNhaP1) is highly selective for Na+ ions. We then characterize the ion selectivity in both the inward-open and outward...
Benzoic acid derivatives are important molecular systems in the pharmaceutical industry. Salicylic acid is distinct among the derivatives of benzoic acid due to the presence of an intra-molecular hydrogen bond. With a view to study the evolution of intra- and inter molecular hydrogen bonding at shorter length scales, in-situ high pressure Raman spectroscopic measurement, angle dispersive x-ray diffraction measurements and density functional theory (DFT) based first principle calculations have be...
Molecular dynamics plays an important role for the biological function of proteins. For protein ligand interactions, changes of conformational entropy of protein and hydration layer are relevant for the binding process. Quasielastic neutron scattering (QENS) was used to investigate differences in protein dynamics and conformational entropy of ligand-bound and ligand-free streptavidin. Protein dynamics were probed both on the fast picosecond timescale using neutron time-of-flight spectroscopy and...
The goal of this work is to provide physical insights into the formation and stability of inclusion complexes in aqueous solution between cyclodextrins (CDs) and a common flame retardant, triphenyl phosphate (TPP). Quantum chemistry calculations reveal the possible energetically favorable geometries of TPP in their 1:1 IC form with α-, β-, and γ-CDs as well as their associated complexation, conformational, and interaction energies. High resolution mass spectrometry (MS) and tandem MS were used w...
Brassinosteroids (BRs) are essential phytohormones which bind to the plant receptor, BRI1, to regulate various physiological processes. The molecular mechanism of the perception of BRs by the ectodomain of BRI1 remains not fully understood. It also remains elusive why a substantial difference in biological activity exists between the BRs. In this work, we study the binding mechanisms of the two most bioactive BRs, brassinolide (BLD) and castasterone (CAT) using molecular dynamics simulations. We...
Terahertz (THz) spectroscopy was used to observe adsorbed water structure and dynamics within polymer films, ultimately providing a strong rationale for the observed rates of water desorption. The THz absorption spectra of nylon-6 films undergo drastic changes during the hydration and drying process. Additionally, the structural change from γ to α crystals, induced by the hydration, was observed by the characteristic band of α-nylon-6 at 6.5 THz. Importantly, the THz spectra of adsorbed water, a...
The excitonic couplings among 54 bacteriochlorophylls-g (BChl)-g, 4 BChl-g’ and 2 Chl-aF pigments were calculated in the type-I homodimeric reaction center of Heliobacterium modesticaldum (hRC), and compared with that in photosystem I (PSI) type-I heterodimeric reaction center. The advanced combination of transition charge of electrostatic-potential with the Poisson equation (Poisson-TrESP), applied for the first time to the excitonic coupling calculation, gave a reliable model in contrast to a ...
Top fields of study
Analytical chemistry
Inorganic chemistry
Molecular dynamics