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Disulfide Bond

A disulfide bond is a strong link formed between two sulfur atoms from cysteine amino acids in a protein. These bonds help maintain the protein's 3D shape, which is crucial for its function.

Example

Disulfide bonds in insulin help hold its two chains together, allowing it to work as a hormone.

Formation

Disulfide bonds form when two cysteine residues come close together and their sulfur atoms create a covalent bond. This can happen:

  • Within the same protein chain (intramolecular)
  • Between different protein chains (intermolecular)

Functions

  • Structural stability - Maintain protein shape
  • Protein folding - Guide proper folding
  • Resistance to denaturation - Protect against unfolding
  • Functional integrity - Preserve active conformations

Clinical Significance

Variants affecting cysteine residues can:

  • Disrupt disulfide bond formation
  • Destabilize protein structure
  • Cause protein misfolding
  • Lead to loss of function