# 1.2 Electrostatics & Salt Bridges

> Electrostatics & Salt Bridges (Module 1: The Building Blocks). Key concept: Charge complementarity & distance. Identify which side chains carry charge at physiological pH.

Electrostatics & Salt Bridges (Module 1: The Building Blocks). Key concept: Charge complementarity & distance. Identify which side chains carry charge at physiological pH.

- Identify which side chains carry charge at physiological pH
- Explain how a salt bridge forms and what distance range it needs (about 2.7–4 Å)
- Explain why histidine’s charge depends on pH, and why that makes it useful

## Links

- [Module 1: The Building Blocks](https://proteindesign.academy/module/1)
- [Introduction](https://proteindesign.academy/module/1/intro)
- [1.1 The Hydrophobic Effect](https://proteindesign.academy/module/1/1)
- [1.3 Size & Shape: The Packing Game](https://proteindesign.academy/module/1/3)
- [1.4 The Special Characters](https://proteindesign.academy/module/1/4)
- [1.5 Aromatic Interactions](https://proteindesign.academy/module/1/5)
- [The Peptide Engineer](https://proteindesign.academy/module/1/capstone)