Name: Important Sources of Vitamins
Uploaded: 2019-07-19
Duration: 2 min 57 s
Description: Vitamins are essential for several biochemical reactions and the development of the body. This video describes their sources, types based on their solubility...

Question

What type of bonding exists in

α

-helix configuration and

β

-sheet?

Accepted Answer

$α$ -helix structure is the most common structure in which a polypeptide chain forms all possible hydrogen bonds by twisting into the right-handed helix with the $- NH$ group of each amino acid residue hydrogen-bonded to the $C = O$ of an adjacent turn of the helix. In $α$ -helix, the size of R groups is quite large and H-bonds are formed between the $> C = O$ of one amino acid and the $> N - H$ of the fourth amino acid residue in the peptide chain. The structure is stabilized by the intermolecular hydrogen bond between amide hydrogen( $> N - H$ group) and the carbonyl oxygen( $> C = O$ group) of the fourth amino acid residue away in the peptide chain. Although the hydrogen bond is fairly weak, their large number stabilizes the structure. Therefore, the bonding in $α$ -helix structure of a protein is hydrogen bonding.

Fig- $α$ -helix structure of the protein

When an atom in protein molecule are joined to one another through covalent bonds to form chains. On hydrolysis, all protein gives $α$ -amino acids joined by polypeptide linkage. Therefore, the linkage which are responsible for the formation of $β$ -sheet structure is polypeptide bonds. This was proposed by Linus Pauling which states that all the polypeptide chains are stretched out to nearly maximum extension and then laid side by side in a zig-zig manner to form flat sheet held by hydrogen bond. This resembles the pleated folds drapery that are stacked one upon another to form a $3 D$ structure. They are of two types- parallel and antiparallel.

Fig-Structure of $β$ -sheet

What type of bonding exists in $α$ -helix configuration and $β$ -sheet?

Important Questions on Biomolecules

Learn and Prepare for any exam you want !

What type of bonding exists in α-helix configuration and β-sheet?

Important Questions on Biomolecules

Learn and Prepare for any exam you want !

What type of bonding exists in $α$ -helix configuration and $β$ -sheet?