Sandbox Reserved 1380
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== Structural highlights == | == Structural highlights == | ||
| - | Hemoglobin comprises of four subunits, each having one polypeptide chain and one heme group. First, hemoglobin captures oxygen and transports it through the bloodstream by binding oxygen to each of its heme groups. These <scene name=> | + | Hemoglobin comprises of four subunits, each having one polypeptide chain and one heme group. First, hemoglobin captures oxygen and transports it through the bloodstream by binding oxygen to each of its heme groups. These <scene name='User:Jaime_Prilusky/How_do_we_get_the_oxygen_we_breathe/Four_hemes/3'>molecule</scene> are non-protein chemical compounds that are associated with hemoglobin and are necessary for its function. Each heme is a ring molecule made of C, N, O, and H with a single Fe2+ ion in the middle. Each heme is held in place within the monomer by a hydrophobic interactions and a covalent bond between the iron ion and a nitrogen atom in the side chain of what is termed the proximal histadine. Another histidine, termed the distal histadine, helps in oxygen binding by preventing oxidation of the iron atom (which would prevent oxygen from binding) and by preventing other molecules from binding. |
When oxygen binds to the heme, a conformational change in the hemoglobin monomer takes place. The difference in conformation between the oxygenated and deoxygenated monomer turns out to be crucial for the function of hemoglobin. Thus, when one monomer in a deoxygenated hemoglobin molecule binds oxygen, that monomer’s conformation change forces a similar conformation change in the remaining three monomers, causing them to adopt a conformation more favorable to oxygen binding. This allows for accelerated binding and is known as cooperative binding. | When oxygen binds to the heme, a conformational change in the hemoglobin monomer takes place. The difference in conformation between the oxygenated and deoxygenated monomer turns out to be crucial for the function of hemoglobin. Thus, when one monomer in a deoxygenated hemoglobin molecule binds oxygen, that monomer’s conformation change forces a similar conformation change in the remaining three monomers, causing them to adopt a conformation more favorable to oxygen binding. This allows for accelerated binding and is known as cooperative binding. | ||
Revision as of 20:09, 1 March 2018
| This Sandbox is Reserved from January through July 31, 2018 for use in the course HLSC322: Principles of Genetics and Genomics taught by Genevieve Houston-Ludlam at the University of Maryland, College Park, USA. This reservation includes Sandbox Reserved 1311 through Sandbox Reserved 1430. |
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Sandbox Page: Hemoglobin
Function
A protein called (Hb), seen on the right, is eukaryotes' solution to transporting oxygen to our cells. These hemoglobin proteins are essential to our body as they serve as vehicles that transport oxygen across the body. In general, oxygen binds to hemoglobin in oxygen-rich areas like the lungs, and then the hemoglobin cleaves off in oxygen-poor areas such as the other cells across the body. Via this simple yet intricate mechanism, hemoglobin can supply oxygen to all cells.
Structural highlights
Hemoglobin comprises of four subunits, each having one polypeptide chain and one heme group. First, hemoglobin captures oxygen and transports it through the bloodstream by binding oxygen to each of its heme groups. These are non-protein chemical compounds that are associated with hemoglobin and are necessary for its function. Each heme is a ring molecule made of C, N, O, and H with a single Fe2+ ion in the middle. Each heme is held in place within the monomer by a hydrophobic interactions and a covalent bond between the iron ion and a nitrogen atom in the side chain of what is termed the proximal histadine. Another histidine, termed the distal histadine, helps in oxygen binding by preventing oxidation of the iron atom (which would prevent oxygen from binding) and by preventing other molecules from binding.
When oxygen binds to the heme, a conformational change in the hemoglobin monomer takes place. The difference in conformation between the oxygenated and deoxygenated monomer turns out to be crucial for the function of hemoglobin. Thus, when one monomer in a deoxygenated hemoglobin molecule binds oxygen, that monomer’s conformation change forces a similar conformation change in the remaining three monomers, causing them to adopt a conformation more favorable to oxygen binding. This allows for accelerated binding and is known as cooperative binding.
In terms of the second part of each subunit, the polypeptide chains of adult hemoglobin themselves are of two kinds, known as alpha and beta chains, similar in length but differing in amino acid sequence. Specially, the image shown is that of the delta chain in the beta chain. This is the .
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