biostudies-literatureUnknown14(6)Takano YWe present a brief review of our recent computational studies of hydrogen bonds (H-bonds) in helical secondary structures of proteins, α-helix and 3₁₀-helix, using a Negative Fragmentation Approach with density functional theory. We found that the depolarized electronic structures of the carbonyl oxygen of the <i>i</i>th residue and the amide hydrogen of the (<i>i</i> + 4)th residue cause weaker H-bond in an α-helix than in an isolated H-bond. Our calculations showed that the H-bond energies in the 3₁₀-helix were also weaker than those of the isolated H-bonds. In the 3₁₀-helices, the adjacent N-H group at the (<i>i</i> + 1)th residue was closer to the C=O group of the H-bond pair than the adjacent C=O group in the 3₁₀-helices, whereas the adjacenBiophysical reviews1369-1378https://www.ebi.ac.uk/biostudies/studies/S-EPMC9842822biostudies-literatureQuantum chemical studies on hydrogen bonds in helical secondary structures.PMC9842822Nakamura HTakano YKondo HXfalseQuantum chemical studies on hydrogen bonds in helical secondary structures.We present a brief review of our recent computational studies of hydrogen bonds (H-bonds) in helical secondary structures of proteins, α-helix and 3₁₀-helix, using a Negative Fragmentation Approach with density functional theory. We found that the depolarized electronic structures of the carbonyl oxygen of the <i>i</i>th residue and the amide hydrogen of the (<i>i</i> + 4)th residue cause weaker H-bond in an α-helix than in an isolated H-bond. Our calculations showed that the H-bond energies in the 3₁₀-helix were also weaker than those of the isolated H-bonds. In the 3₁₀-helices, the adjacent N-H group at the (<i>i</i> + 1)th residue was closer to the C=O group of the H-bond pair than the adjacent C=O group in the 3₁₀-helices, whereas the adjacen2022-01-01T00:00:00Z2022 Dec2025-04-04T08:28:39.467Z2025-02-19T04:00:13.87ZS-EPMC98428223665998810.1007/s12551-022-01034-5