What is the structural feature of an α-helix related to dipole moments?

The structural feature of an α-helix related to dipole moments is accurately captured by the idea that it is formed from the accumulated or added dipole moments of all hydrogen bonds within the helix. In an α-helix, the backbone amide hydrogen bonds to the carbonyl oxygen of the residue four positions earlier, thereby creating a repeating pattern of hydrogen bonding. This consistent orientation of the amide groups generates a net dipole moment along the helix, contributing to its stability and overall structure.

This arrangement leads to the orientation of the molecular dipoles resulting in a helix with a significant macroscopic dipole moment. Each hydrogen bond contributes to the overall electric field, amplifying the dipole effect across the entire structure of the α-helix. This characteristic helps to stabilize the helix and is an important factor when considering protein folding and function.

The emphasis on the accumulation of dipole moments highlights the importance of the hydrogen bond network in creating and maintaining the helical structure, making it a fundamental aspect of α-helical conformations in proteins.