A QM/MM study of the complexes formed by aluminum and iron with serum transferrin at neutral and acidic pH.

Serum transferrin (sTf) transports iron in serum and internalizes in cells via receptor mediated endocytosis. Additionally, sTf has been identified as the predominant aluminum carrier in serum. Some questions remain unclear about the exact mechanism for the metal release or whether the aluminum and iron show the same binding mode during the entire process.

Piris natural orbital functional study of the dissociation of the radical helium dimer.

We have investigated the dissociation behavior of the radical helium dimer He(2) (+) using the Piris natural orbital functional (PNOF). This system is particularly challenging to be described by standard density functionals. The restricted open formulation of the PNOF-2, as well as the PNOF-2 energy plus the extended Koopmans' vertical ionization potential calculations of the neutral helium dimer, have been tested for calculating the ground-state energies of He(2) (+) as a function of the internuclear distance.

Correlation holes for the helium dimer.

We have investigated the radial electron pair probability distributions (REPPDs) of the helium dimer within the Piris natural orbital functional (PNOF) theory. The analytical formulas to evaluate intracule densities, Fermi, Coulomb, and total correlation holes using our reconstruction functional PNOF-2 [J. Chem.

Reaction mechanism of the acidic hydrolysis of highly twisted amides: Rate acceleration caused by the twist of the amide bond.

We present an ab initio study of the acid hydrolysis of a highly twisted amide and a planar amide analogue. The aim of these studies is to investigate the effect that the twist of the amide bond has on the reaction barriers and mechanism of acid hydrolysis. Concerted and stepwise mechanisms were investigated using density functional theory and polarizable continuum model calculations.

Water-promoted hydrolysis of a highly twisted amide: rate acceleration caused by the twist of the amide bond.

The water-promoted hydrolysis of a highly twisted amide is studied using density functional theory in conjunction with a continuum dielectric method to introduce bulk solvent effects. The aim of these studies is to reveal how the twisting of the C-N bond affects the neutral hydrolysis of amides. To do so, both concerted and stepwise mechanisms are studied and the results compared to the ones from the hydrolysis of an undistorted amide used as reference.