Alpha helix is which structure
Ans. (b) SecondaryStructural organization of amino acid can be of following types:* Primary structure:# Linear sequence of amino acid, held together by peptide bond (a type of covalent bond).* Secondary structure:# Folding of short ~ 3-30 residue, contiguous segment of polypeptide.# Joined together by non-covalent bond primarily.* Hydrogen bond: Most important bond* Vander walls force* Hydrophobic bond* Electrostatic bond* Tertiary structure: 3D conformation of polypeptide. Bonds are non-covalent (similar to secondary structure)* Quaternary structure:# When more than one polypeptide aggregate to form one functional protein. The spatial relationship between these polypeptide subunit is called quaternary structure.# Bonds are non-covalent (similar to secondary structure)Alpha Helix* It is an example of secondary structure.* It is the most common and stable secondary structure. Right handed spiral* Each turn of alpha helix is formed by 3.6 amino acyl residues.* Size of 1 turn of alpha helix: 0.54 nm* Proteins whose major secondary structure is alpha-helix:# Hemoglobin and Myoglobin
Primary
Secondary
Tertiary
Quaternary
Proteins and Amino Acids