View of Sperm Whale Oxygenated Myoglobin Dimer.  Oxygenated Myoglobin (Oxy Mb) is a dimeric oxygen binding protein found in muscle cells.  The Mb dimer contains one heme group.  The heme group is displayed in various views, but can also be turned on and off using the "Ligands" bottons.  The Oxygenated form of myolgobin provides the muscle mitochondria with the oxygen is needs for ATP synthesis.