In a protein, certain domains may form specific structures
such as α helix and β strand, which constitute the secondary structure of the protein.
Figure 2-C-1. The secondary structure of RNase
A, which contains three α helices and seven β strands.
Figure 2-C-2. The α helix and β
strand in RNase A. (a) Residues 1 to 36. (b) Residues 80 to 85. PDB ID = 1RCN.