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.

• 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