Fig. 3: H-bonds in polyproline II helical bundle assemblies.
From: Hydrogen bonding patterns and cooperativity in polyproline II helical bundles
A Possible H-bonds/interactions between PPII helices in a 2D PPII helical bundle: CO···HN (purple), CO···HαCα front (yellow), CO···HαCα inner (orange) and CO···HαCα outer (magenta). B Simplified structures for CO···HN (formamide), CO···HαCα front (acetaldehyde), CO···HN + CO···HαCα front (acetamide), CO···HαCα inner (acetaldehyde), CO···HαCα outer (N-methylformamide) and CO···(Hα)2Cα inner+outer (N-(2-oxoethyl)formamide) H-bonds/interactions.
