6 Major chemical bonds in Proteins
In this post let me give you a quick summary of major bonds in Proteins.
Proteins are biomolecules made up of amino acids joined by peptide bond.
1. Peptide bond
- Peptide bond is formed when a water molecule is eliminated during a reaction between
- –NH2 (amino group) of one amino acid and –COOH (carboxyl group) of another.
Peptide bond or amide bond Characteristics
watch this video on peptide bond for more clarity of concept
- Covalent bond that joins 2 amino acids
- Dehydration synthesis: release of H2O
- Partial double bond character: as shorter than a single bond
- Rigid and planar: rotation around the bond is restricted
- Trans configuration: less steric hindrances of adjacent amino acid side chains
- Uncharged : only side chains and N and C terminals are charged.
2. Disulfide bonds: covalent bond formed between Sulphur containing amino acid
- It forms when the -SH groups of two cysteine residues are covalently linked as a dithiol by oxidation
- It may be formed between different chains of amino acids or between different parts of the chain.
- It provide some rigidity to the protein molecule.
3. Hydrophobic Bond
- It is formed between two non polar groups or hydrophobic amino acids.
- Hydrophobic bonding forms an interior, hydrophobic protein core, where most hydrophobic side chains can closely associate and are shielded from interactions with solvent water.
- Most important driving force in protein folding
4. Hydrogen Bond
- A hydrogen bond is the electromagnetic attractive interaction between polar molecules, in which hydrogen is bound to a highly electronegative atom, such as nitrogen, oxygen or fluorine. It is a weak bond.
- Amino acids with side chain containing –OH, -NH2 etc participate in H-bonding
5. Ionic Bond
- Ionic bond forms due to attractive force between oppositely charged ionised groups.
- Refer the above figure where aspartic acid is negatively charged and lysine is positively charged
- The Van der Waals force is a transient, weak electrical attraction of one atom for another.
- It is the sum total of all non covalent associations between electrically neutral molecules.
Watch this video on bonds in proteins for better understanding. Thank you