It has been demonstrated that sulfur-sulfur interactions can exist in various molecular systems. In this work we investigated sulfur-sulfur interactions in crystal structures of small molecules by analyzing geometric data from the Cambridge Structural Database (CSD) and by quantum chemical calculations. The analysis of cysteine residues (R-CH 2 SH) in the crystal structures from the CSD indicates that in the sulfur-sulfur interactions the preferred is parallel orientation of two C-S-H planes. Quantum chemical calculations were performed on model systems of methanethiol dimers. The most stable geometry of methanethiol dimer with parallel orientation of C-S-H planes is significantly strong; the interaction energy is -1.80 kcal/mol calculated at the very accurate CCSD(T)/CBS level. However, the strongest sulfur-sulfur Author Contributions: I.S.A. performed quantum chemical calculations, interpreted the data, and prepared the manuscript.; G.V.J. proposed topic and performed CSD search.; M.K.M. has done SAPT, QTAIM and NCI index method calculations and analyzed data.; S.D.Z. analyzed the results, supervised, wrote and edited the manuscript.

Peanut grain digestion by oral and gastric phase enzymes generates mixture of products, where the major peanut allergens remain intact and their digested peptides have preserved allergenic capacity highlighting their important roles in allergic reactions to peanut.

The ratios of E/Z isomers of sixteen synthesized 1,3-dihydro-3-(substituted phenylimino)-2H-indol-2-one were studied using experimental and theoretical methodology. Linear solvation energy relationships (LSER) rationalized solvent influence of the solvent-solute interactions on the UV-Vis absorption maxima shifts (ν) of both geometrical isomers using the Kamlet-Taft equation. Linear free energy relationships (LFER) in the form of single substituent parameter equation (SSP) was used to analyze substituent effect on pK, NMR chemical shifts and ν values. Electron charge density was obtained by the use of Quantum Theory of Atoms in Molecules, i.e. Bader's analysis. The substituent and solvent effect on intramolecular charge transfer (ICT) were interpreted with the aid of time-dependent density functional (TD-DFT) method. Additionally, the results of TD-DFT calculations quantified the efficiency of ICT from the calculated charge-transfer distance (D) and amount of transferred charge (Q). The antimicrobial activity was evaluated using broth microdilution method. 3D QSAR modeling was used to demonstrate the influence of substituents effect as well as molecule geometry on antimicrobial activity.

Conglutins represent the major peanut allergens and are renowned for their resistance to gastro-intestinal digestion. Our aim was to characterize the digestion-resistant peptides (DRPs) of conglutins by biochemical and biophysical methods followed by a molecular dynamics simulation in order to better understand the molecular basis of food protein allergenicity. We have mapped proteolysis sites at the N- and C-termini and at a limited internal segment, while other potential proteolysis sites remained unaffected. Molecular dynamics simulation showed that proteolysis only occurred in the vibrant regions of the proteins. DRPs appeared to be conformationally stable as intact conglutins. Also, the overall secondary structure and IgE-binding potency of DRPs was comparable to that of intact conglutins. The stability of conglutins toward gastro-intestinal digestion, combined with the conformational stability of the resulting DRPs provide conditions for optimal exposure to the intestinal immune system, providing an explanation for the extraordinary allergenicity of peanut conglutins.

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Fluorination of compounds causes an increase in the proton-donating ability and a decrease in the proton-accepting capacity of groups in their vicinity. The formation of F···F interactions is followed by the shift of the electron density in the area of F···F contact, which creates a new region with a larger surface area, a higher negative potential, and, hence, a more pronounced accepting ability. The new region also has a greater ability to form multiple (simultaneous) interactions with species from the environment, thus compensating for the reduction of the accepting capacity of the groups in the vicinity. This phenomenon explains not only the abundance of F···F interactions in crystal structures, but also a large number of structures with F···O interactions. Only C–H···F interactions are more numerous than F···F interactions in crystal structures, which indicates a high affinity of fluorinated compounds for nonpolar groups.

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