Peptides Bond Structure

Peptides are short polymers of amino acids linked by peptide (amide) bond.

The Peptide bond

  • Formed by reaction of the carboxyl group of one amino acid with the amine group of another amino acid.
  • 1 molecule of water is released as a result

This leads to creation of multiple flat areas (not all in the same plane) in the peptides molecule, hence the structure becomes stable.

Peptide Structure can be classified into 4 levels:-

  • Primary Structure
  • Secondary Structure
  • Tertiary Structure
  • Quaternary Structure

Primary Structure

Amino acids are bonded from N-terminus to C-terminus in the primary sequence

Secondary Structure

Intramolecular Hydrogen bonds leads to 3 different motifs:

  • α-Helix
  • It is spiral down clockwise
  • Hydrogen Bonds are formed between the carboxyl oxygen and the amine hydrogen.
  • Side chains point away from the coil
  • β-Sheet
  • Hydrogen may or may not be parallel
  • Side chains stick out above and below
  • More rigid but less elastic than α-Helix


  • Coil

Complicated structure but not random

Ternary Structure

  • The 3D positions of atoms in space is determined by side chain and its interaction with the environment.


  • Hydrophilic side chain: It points outside in polar environment and points inside in non-polar
  • Hydrophobic side chain: It points inside in polar environment and points outside in non-polar


  • Disulphide bonds present also affect the 3D structure

Quaternary Structure

It is an assortment of subunits by non-covalent molecular bonds like Hydrogen bonds

Pharmaceutical industry is among the top most industries in the world today which works with over billions of dollars. There are various companies that aids to helping by researching and manufacturing the best medications for better and affordable rates across the world. Peptides production is also manufactured by companies across the world for betterment of the world population.


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