In the light of occurrence bacterial strains with multiple resistances against most antibiotics, antimicrobial peptides that interact outer layer Gram-negative bacteria, such as polymyxin (PMX), have recently received increased attention. Here we present a study interactions PMX-B, -E, and -M lipopolysaccharide (LPS) from deep rough mutant strain Escherichia coli. A method for efficient purification biosynthetically produced LPS using reversed-phase high-performance liquid chromatography in...

We apply the Kurland–McGarvey (J. Magn. Reson. 1970, 2, 286) theory for NMR shielding of paramagnetic molecules, particularly its special case limited to ground-state multiplet characterized by zero-field splitting (ZFS) interaction form S·D·S. The correct formulation this problem was recently presented Soncini and Van den Heuvel Chem. Phys. 2013, 138, 054113). With effective electron spin quantum number S, involves 2S+1 states, which all but one are low-lying excited between magnetic...

We apply the theory of nuclear magnetic resonance (NMR) chemical shift for paramagnetic systems to demanding cobalt(II) complexes. Paramagnetic NMR (pNMR) results by density-functional (DFT) can be very far from experimental values. Therefore, it is interest investigate applicability electron-correlated ab initio computational methods achieve useful accuracy. Here, we use wave function based electronic structure calculate pNMR within theoretical framework established recently. applied...

Abstract Long‐range pseudo‐contact NMR shifts (PCSs) provide important restraints for the structure refinement of proteins when a paramagnetic metal center is present, either naturally or introduced artificially. Here we show that ab initio quantum‐chemical methods and modern version Kurland–McGarvey approach (pNMR) in presence zero‐field splitting (ZFS) together accurate predictions all PCSs metalloprotein (high‐spin cobalt‐substituted MMP‐12 as test case). Computations 314 13 C using g ‐...

Guest capture and release are important properties of self-assembling nanostructures. Over time, a significant fraction guests might engage in short-lived states with different symmetry stereoselectivity transit frequently between multiple environments, thereby escaping common spectroscopy techniques. Here, we investigate the cavity an iron-based metal organic polyhedron (Fe-MOP) using spin-hyperpolarized

We apply approximate relativistic methods to calculate the magnetic property tensors, i.e., g-tensor, zero-field splitting (ZFS) tensor (D), and hyperfine coupling (HFC) for purpose of constructing paramagnetic nuclear resonance (pNMR) shielding tensors. The chemical shift anisotropy are calculated by applying a modern implementation classic Kurland-McGarvey theory ( J. Magn. Reson. 1970 , 2 286 ), which formulates in terms g- HFC tensors obtained ground multiplet, case higher than doublet...

Abstract Long‐range pseudo‐contact NMR shifts (PCSs) provide important restraints for the structure refinement of proteins when a paramagnetic metal center is present, either naturally or introduced artificially. Here we show that ab initio quantum‐chemical methods and modern version Kurland–McGarvey approach (pNMR) in presence zero‐field splitting (ZFS) together accurate predictions all PCSs metalloprotein (high‐spin cobalt‐substituted MMP‐12 as test case). Computations 314 13 C using g ‐...

The aqueous solution of the Ni(2+) ion was investigated using a first principles molecular dynamics (FPMD) simulation based on periodic density-functional theory (DFT) calculations. Statistical averages magnetic properties corresponding to triplet spin state ion, hyperfine coupling, g and zero-field splitting tensors, as well resulting paramagnetic nuclear resonance (pNMR) shielding terms were calculated DFT from instantaneous snapshots extracted FPMD trajectory. We report comprehensive...

Transition metal complexes can possess a large magnetic susceptibility anisotropy, facilitating applications such as paramagnetic tags or shift agents in nuclear resonance (NMR) spectroscopy. Due to its g-shift and zero-field splitting (ZFS) we demonstrate on Co(ii) clathrochelate with an aliphatic 16-carbon chain, modern approach for ab initio calculation of susceptibility. linear dimension but relatively low number atoms, the chosen complex is especially well-suited testing long-range...

We exploited 129Xe NMR to investigate xenon gas uptake and dynamics in a porous liquid formed by dissolving organic cages cavity-excluded solvent. Quantitative shows that when the amount of added sample is lower than present (subsaturation), absorbs almost all atoms from phase, with 30% occupied Xe atom. A simple two-site exchange model enables an estimate chemical shift cages, which good agreement value provided first-principles modeling. T2 relaxation times allow determination rate between...

The aqueous solution of Ni(2+) was investigated using first principles molecular dynamics (FPMD) simulation based on periodic density-functional theory (DFT) calculations. experimental structural parameters the Ni(aq) complex are reproduced well by simulation. An exchange event water molecule in solvation shell is observed, supporting proposed dissociative mechanism exchange. calculated dynamic characteristics surrounding molecules indicate too slow translational diffusion comparison to...

The ability to quantitatively predict and analyze the rate of electron spin relaxation open-shell systems is important for paramagnetic resonance nuclear magnetic spectroscopies. We present a combined molecular dynamics (MD), quantum chemistry (QC), simulation method calculating such rates. based on sampling MD trajectory by QC calculations, produce instantaneous parameters Hamiltonian used, in turn, numerically solve Liouville-von Neumann equation time evolution density matrix. demonstrate...

Ni(2+)(aq) has been used for many decades as a model system paramagnetic nuclear magnetic resonance (pNMR) relaxation studies. More recently, its properties and also rates have studied computationally. We calculated electron NMR parameters using quantum-mechanical (QM) computation of molecular dynamics snapshots, obtained polarizable empirical force field. Statistical averages hyperfine coupling, g- zero-field splitting tensors, well the pNMR shielding terms, are compared to available...

The 129Xe chemical shift in an aqueous solution exhibits a non-monotonic temperature dependence, featuring maximum at 311 K. This is contrast to most liquids, where the monotonic decrease of follows that liquid density. In particular, water occurs higher than We replicate this behaviour qualitatively via molecular dynamics simulation and computing for snapshots trajectory. also construct semianalytical model, which Xe atom occupies cavity constituted by spherical shell, consisting even...

An adatom on a graphene surface may carry magnetic moment causing spin-half paramagnetism. This theoretically predicted phenomenon has recently also been experimentally verified. The measurements of defect-induced magnetism are mainly based magnetometric techniques where artifacts such as environmental impurities hard to rule out. Spectroscopic methods electron spin resonance (ESR) and paramagnetic nuclear (pNMR) conventionally used in the development materials, e.g., study centers. present...

The minimal model system to study the basic principles of protein folding is hairpin. formation beta-hairpins, which are components antiparallel beta-sheets, has been studied extensively in past decade, but much less known about helical hairpins. Here, we probe hairpin between a polyproline type-II helix and an alpha-helix as present natural miniprotein peptide YY (PYY). Both turn sequence interactions aromatic side chains from C-terminal with pockets formed by N-terminal Pro residues shown...

Functionalized cages encapsulating xenon atoms enable highly sensitive, background-free molecular imaging through a technique known as HyperCEST 129Xe MRI. Here, we introduce class of potential biosensor cage structures based on two resorcinarene macrocycles bridged either by aliphatic carbon chains or piperazines. First-principles-based modeling predicts high chemical shift (about 345 ppm) outside the typical experimental observation window for encapsulated aliphatically and resonances...

Spin-exchange optical hyperpolarization of $^{129}\mathrm{Xe}$ gas enhances the signal-to-noise ratio in nuclear magnetic resonance experiments. The governing parameter Rb-Xe spin-exchange process, so-called enhancement factor, was recently reevaluated experimentally. However, underlying hyperfine coupling and atomic interaction potential as functions internuclear distance open-shell dimer have not been accurately determined to date. We present a piecewise approximation based on...

Solvent-induced carbon-13 NMR chemical shifts of nine candidate antenna molecules were analysed using a dynamic solvation model, revealing the distinct features perimeter and inside nuclear sites.

Developed multi-step computational protocol successfully models the 13 C NMR shielding tensor of carbonate in paramagnetic Mg 2− x Ni Al-LDH.