Question

In proteins, the hydrogen bonding responsible for the secondary structure of a protein generally takes place between backbone carbonyl oxygen atoms and amide hydrogen atoms. In contrast, the hydrogen bonding that contributes to tertiary structure generally occurs between amino acid side chains.

Two serine residues are shown below, with possible hydrogen bonds shown in green. Which bonds depict the hydrogen bonding that occurs between serine residues and contributes to tertiary structure?

Answer 1

Concepts and reason

Hydrogen bond is a non-covalent bond formed intermolecularly or intramolecularly by electrostatic interactions between a hydrogen atom and two electronegative atoms such as nitrogen, oxygen, and fluorine.

Fundamentals

To form a hydrogen bond, a hydrogen bond donor and an acceptor are required. The H-bond donor has a hydrogen atom bonded to a highly electronegative atom that pulls electron density away from the hydrogen atom resulting in partially positive charge on hydrogen and in turn, this partial positive charge is attracted to the partial negative charge present on the hydrogen bond acceptor, resulting in the formation of a straight, liner structure.

Hydrogen bond plays a crucial role in the protein structures, as it stabilizes the secondary, tertiary, and quaternary structures of the proteins. The hydrogen bond connects the amino acids between different polypeptide chains in the protein by dipole-dipole force.

The tertiary structure of the protein depicts the way the entire chain folds itself into a final 3 dimensional structure.

The hydrogen bonding that occurs between the two serine molecules depicts the tertiary structure. In Serine the side chain ${\rm{ - C}}{{\rm{H}}_{\rm{2}}}{\rm{ - O - H}}$ is involved in hydrogen bonding

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