Final answer:
The predominant non-covalent interaction seen in alpha-helices and beta-sheets is hydrogen bonding. Hydrogen bonding forms between electronegative atoms in amino acid residues and helps stabilize the helical and sheet-like structures.
Step-by-step explanation:
The predominant non-covalent interaction seen in alpha-helices and beta-sheets is hydrogen bonding.
Hydrogen bonding forms between a highly electronegative oxygen atom or a nitrogen atom and a hydrogen atom attached to another oxygen atom or a nitrogen atom. This type of interaction is extremely important in both the intra- and intermolecular interactions of proteins, including the stabilization of alpha-helices and beta-sheets.
For example, in alpha-helices, hydrogen bonds form between the carbonyl oxygen of one amino acid and the amide hydrogen of another amino acid, creating a helical structure. In beta-sheets, hydrogen bonds form between adjacent amino acid residues, resulting in a sheet-like secondary structure.