3-Dimensional Structure of Proteins
4 levels of protein structure:
Alpha Helix Common structure: ~25% of all amino acid residues! (hair…) Optimal use of internal hydrogen bonding: 1st -4th Alpha-helices are generally right handed
Interactions of R groups with dipole: Stabilizes or destabilizes the alpha helix Alpha helices have an intrinsic dipole: 3 constraints affect stability of alpha helix: 1)interactions between adjacent R groups steric electrostatic 2) Occurrence of Pro and Gly 3) interactions between AAs at end of helix and intrinsic dipole
Characteristics of alpha helices: Not limited to coiled-coils!! Common structural units
Proteins can have mostly alpha helix, beta sheet, or both Other secondary structures also exist! (tomorrow…)