Module 2: The Weaver

Local Structure

Learn how amino acids form secondary structures — alpha helices, beta sheets, and loops.

• Explain the i → i+4 backbone hydrogen bonding that holds an alpha helix together
• Distinguish parallel from antiparallel beta sheets by their hydrogen bond geometry
• Identify the structural roles of loops, turns and the residues that favour them
• Predict where proline and glycine will break regular secondary structure
• Read a Ramachandran plot and explain which backbone geometries are forbidden and why
• Predict secondary structure from sequence alone using residue propensities