# 3.2 Disulfide Bridges

> Disulfide Bridges (Module 3: The Architect). Key concept: Covalent cross-links. Explain how a disulfide differs from every other stabilising interaction by being covalent.

Disulfide Bridges (Module 3: The Architect). Key concept: Covalent cross-links. Explain how a disulfide differs from every other stabilising interaction by being covalent.

- Explain how a disulfide differs from every other stabilising interaction by being covalent
- Apply the geometric requirements: Cα–Cα roughly 4.5–6.5 Å, with a C–S–S–C dihedral near ±90°
- Explain why disulfides matter most for proteins that leave the reducing cytoplasm
- Recognise that two cysteines in a structure do not make a disulfide

## Links

- [Module 3: The Architect](https://proteindesign.academy/module/3)
- [3.1 Building the Hydrophobic Core](https://proteindesign.academy/module/3/1)
- [3.3 Surface vs Buried: The Inside-Out Rule](https://proteindesign.academy/module/3/3)
- [3.4 Domain Architecture](https://proteindesign.academy/module/3/4)
- [3.integration The Protein Repair Shop](https://proteindesign.academy/module/3/integration)
- [The Folding Architect](https://proteindesign.academy/module/3/capstone)