C O N P S
Hemoglobin is found in the red blood cells of the body. The main function of hemoglobin is to transport oxygen from the lungs to the tissues and then transport CO2 back from the tissues to the lungs. One hemoglobin molecule has the ability to transport up to 4 oxygen molecules. There are two forms of hemoglobin: oxyhemoglobin, which is saturated with oxygen molecules and deoxyhemoglobin, which is unsaturated with oxygen molecules.
To see more about how the structure of hemoglobin affects its function use the chime tutorial below!
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The heme molecule is located between helix E shown in green and helix F shown in red.
The histidines in helix E and helix F are highly conserved.
These histidines are located proximally and distally to the heme molecule and keep it in place within the globin protein by
The FG corner of the globin protein is also essential to hemoglobin's function and affects the conformational change between the oxygenated and deoxygenated states. The amino acids in this region are also highly conserved between species. To view the FG corner click
As oxygen binds to oxyhemoglobin it has a higher affinity for additional oxygen molecules, and as oxygen is released from deoxyhemoglobin it has a decreased affinity for additional oxygen molecules. This regulation is known as cooperativity and is a result of conformational changes in the structure of hemoglobin which make the heme molecule more or less accessible to oxygen. There are two structures of hemoglobin: relaxed (R) and tense (T). The conformational shift between these two structures is a result of a rotation between the alpha and beta subunits. To see this, let's look at an alpha and beta dimer
The amino acids that are involved in this conformational change in structures are located at the interface between the alpha and beta dimers and are highlighted. To zoom in click
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