Hydrogen bonds H-bond describes a favorable interaction between a proton bonded to an electronegative atom and an atom carrying a lone pair of electrons: D-H +A D-HA Acceptors (A): Donors (D): This interaction is very important for maintaining protein backbone interactions H-bond describes a favorable interaction between a proton bonded to an electronegative atom and an atom carrying a lone pair of electrons: D-H + A D H A Acceptors (A): Donors (D): This interaction is very important for maintaining protein backbone interactions Hydrogen bonds C N O O H O H O H N