Sandbox GGC10

Hemoglobin

Function

Hemoglobin is an oxygen-transport protein. Hemoglobin is an allosteric protein. It is a tetramer composed of two types of subunits designated α and β, with stoichiometry α2β2. The four subunits of hemoglobin sit roughly at the corners of a tetrahedron, facing each other across a cavity at the center of the molecule. Each of the subunits contains a heme prosthetic group. The heme molecules give hemoglobin its red color. Each individual heme molecule contains one Fe2+ atom. In the lungs, where oxygen is abundant, an oxygen molecule binds to the ferrous iron atom of the heme molecule and is later released in tissues needing oxygen. The heme group binds oxygen while still attached to the hemoglobin monomer. The spacefill view of the hemoglobin polypeptide subunit with an oxygenated heme group shows how the oxygenated heme group is held within the polypeptide. Anchoring of the heme is facilitated by a histidine nitrogen that binds to the iron. A second histidine is near the bound oxygen. The "arms" (propanoate groups) of the heme are hydrophilic and face the surface of the protein while the hydrophobic portions of the heme are buried among the hydrophobic amino acids of the protein.

Structural highlights

This is a sample scene created with SAT to color by Group, and another to make a transparent representation of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.

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