An alpha helix is a common structural motif in proteins, characterized by a right-handed coil or spiral. This structure is stabilized by hydrogen bonds between the backbone atoms in the polypeptide chain, specifically between the carbonyl oxygen of one amino acid and the amide hydrogen of another, typically four residues earlier. Alpha helices are crucial for the overall shape and function of proteins, contributing to their stability and interactions. They are often found in various proteins, including enzymes and structural proteins, and play a significant role in the formation of larger protein structures, such as beta sheets and tertiary structures.