Final answer:
The repeating pattern in a peptide bond's main chain is a result of secondary protein structure, where hydrogen bonding leads to the formation of α-helices and β-pleated sheets within the peptide backbone. The backbone is made up of a repeated -C-C-N- pattern, with hydrogen bonds providing stability and affecting the protein's overall structure.
Step-by-step explanation:
In the case of α-helices, the helix is stabilized by hydrogen bonds between every fourth amino acid, creating a coiled shape.
In contrast, β-pleated sheets are formed by side-by-side polypeptide chains that are held together by hydrogen bonds, creating a folded, pleated shape.
Whether the resulting β-pleated sheets are parallel or antiparallel, they contribute significantly to the stability and final three-dimensional structure of proteins.
The particular sequence of amino acids in a chain, known as the amino acid sequence, also plays a crucial role in how the protein will fold and function.
Although the peptide bond itself is quite rigid, due to resonance structures, the overall polypeptide chain remains flexible, allowing a multitude of potential interactions that drive the folding process.