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3D Structure of Hemoglobin

CPK Color Scheme

Hemoglobin is the protein primarily responsible for providing cells much-needed oxygen throughout the human body. This macromolecule consists of an iron-containing heme group that, when in the lungs, binds to oxygen and then proceed to carry its oxygen content to all the cells in the body.

Reset and spin this Hemoglobin molecule.

Hemoglobin is a tetramer consisting of four polypeptide chains. The two α-globin chains and two β-globin chains are all alpha helices, which can be seen here. Collectively, these secondary structures provide the hemoglobin with its quaternary form.

 The two α-globin chains are displayed here. Notice that these chains are similar in length and size.

The two β-globin chains are displayed here. Notice that these chains are similar in length and size. Does there seem to be any differences between the α-globin chains and β-globin chains in terms of size and length?

Here we can see how the heme group is bound to one of the chains of the hemoglobin. There are four such of these heme groups in every hemoglobin. Notice the large, ring-like structure of the heme group, including the labelled iron atom that is reponsible for oxygen binding. Also notice the location of the distal and proximal histidine chains, which are responsible for stabilizing the heme group. The distal histidine helps ensure that the heme group bind to oxygen and not only carbon waste (Boyer, 2006). Because of its highly useful nature, this specific region is highly conserved.

Works Cited

Boyer R, et al. 2006. Myglobin & Hemoglobin. http://www3.interscience.wiley.com:8100/legacy/college/boyer/0471661791/structure/HbMb/hbmb.htm. February 2010.

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