Unusual Hydrogen Bonds. H···π Interactions

Halogen bonds as orthogonal molecular interactions to hydrogen bonds.

Halogen bonds (X-bonds) are shown to be geometrically perpendicular to and energetically independent of hydrogen bonds (H-bonds) that share a common carbonyl oxygen acceptor. This orthogonal relationship is accommodated by the in-plane and out-of-plane electronegative potentials of the oxygen, which are differentially populated by H- and X-bonds. Furthermore, the local conformation of a peptide...

Hydrogen Bonds

Interplay of hydrogen bonds and n→π* interactions in proteins.

Protein structures are stabilized by multiple weak interactions, including the hydrophobic effect, hydrogen bonds, electrostatic effects, and van der Waals interactions. Among these interactions, the hydrogen bond is distinct in having its origins in electron delocalization. Recently, another type of electron delocalization, the n→π* interaction between carbonyl groups, has been shown to play a...

Insufficiently dehydrated hydrogen bonds as determinants of protein interactions.

The prediction of binding sites and the understanding of interfaces associated with protein complexation remains an open problem in molecular biophysics. This work shows that a crucial factor in predicting and rationalizing protein-protein interfaces can be inferred by assessing the extent of intramolecular desolvation of backbone hydrogen bonds in monomeric structures. Our statistical analysis...

n→π* Interactions Are Competitive with Hydrogen Bonds.

Because carbonyl groups can participate in both hydrogen bonds and n→π* interactions, these two interactions likely affect one another. Herein, enhancement of an amidic n→π* interaction is shown to reduce the ability of β-keto amides to tautomerize to the enol, indicating decreased hydrogen-bonding capacity of the amide carbonyl group. Thus, an n→π* interaction can have a significant effect on ...