Question

In an α helix, the amino acids get oriented in such a manner that the carbonyl (C=O) group of the nth amino acid can form a hydrogen bond with the amido (N-H) group of the (n+4)^​th amino acid.

Answer 1

The α helix in proteins is a spiral structure stabilized by hydrogen bonds between the carbonyl and amide groups of amino acids that are four residues apart, with 3.6 residues per turn and R groups protruding outward.

Step-by-step explanation:

In an α helix, a common structural component of proteins, the polypeptide chain acquires a spiral coil shape that turns clockwise from the N-terminus to the C-terminus. This structure is stabilized by intrachain hydrogen bonds that form between the carbonyl oxygen (C=O) of one amino acid and the amide hydrogen (N-H) of an amino acid positioned four residues ahead (the n+4th amino acid).

Each turn of the α helix encompasses approximately 3.6 amino acid residues. The side chains, denoted as 'R' groups, protrude outward from the helix core, allowing for the helix's structural integrity without steric hindrance between these chains.

The α-helix is just one type of secondary structure found in proteins, with the β-pleated sheet being another common structure. These arrangements are critical in determining the overall shape and function of the protein. In the β-pleated sheet, the pleats are formed by hydrogen bonding between segments of the polypeptide chain. The R groups extend from the pleated backbone, also allowing the structure to maintain its shape and stability.