Clarke Earley, Ph.D.
Department of Chemistry
Kent State University Stark Campus
North Canton, OH 44720
Shown below is a 3D model of the myoglobin molecule. The primary role of myoglobin is for storage of oxygen. The structure below is the oxygenated form of sperm whale myoglobin, taken from the RCSB Protein Database (structure ref = 1A6M, authors = J. Vojtechovsky, K. Chu, J. Berendzen, R. M. Sweet, & I. Schlichting).
While it appears from this image that proline is present in one of the alpha helices, the original data file indicates that the alpha-helix actually 'breaks' at this point and that it does NOT actually include the proline.