Oxymyoglobin is shown with layers of water bound to its surface. This water is strongly attracted to the protein and is part of the crystal structure. Removing the reveals that the overall tertiary shape is much like a hockey puck. The is a prominent secondary structural component. Since the secondary structures of myoglobin and oxymyoglobin are essentially identical, go to Myoglobin for more detail on the secondary structure. The а-helices can be shown to form , and myoglobin can be classified as an antiparallel α-helix type of globular protein. The shows most of the residues involved in an α-helix are clustered in the area of the plot where one would expect them to be. (Review Ramachandran Plot.) Many of the residues that are outside of the expected cluster are at the end of a helix, and it is not unusual for such residues to have ψ and φ values that are outside of the normal range. Also notice that many of the residues that are in the quadrants on the right are Gly. (Residues can be identified by hovering over the sphere with the cursor.) The prosthetic group of myoglobin is a , and as shown here it is inserted into a nonpolar pocket in the protein. Review heme structure. is attached to one side of the heme and molecular oxygen is attached to the other side.
