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| | == Function == | | == 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.
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| - | 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.
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| - | 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.
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| | == Disease == | | == Disease == |
| - | [HBA_HUMAN] Defects in HBA1 may be a cause of Heinz body anemias (HEIBAN) [MIM:140700]. This is a form of non-spherocytic hemolytic anemia of Dacie type 1. After splenectomy, which has little benefit, basophilic inclusions called Heinz bodies are demonstrable in the erythrocytes. Before splenectomy, diffuse or punctate basophilia may be evident. Most of these cases are probably instances of hemoglobinopathy. The hemoglobin demonstrates heat lability. Heinz bodies are observed also with the Ivemark syndrome (asplenia with cardiovascular anomalies) and with glutathione peroxidase deficiency.[1] Defects in HBA1 are the cause of alpha-thalassemia (A-THAL) [MIM:604131]. The thalassemias are the most common monogenic diseases and occur mostly in Mediterranean and Southeast Asian populations. The hallmark of alpha-thalassemia is an imbalance in globin-chain production in the adult HbA molecule. The level of alpha chain production can range from none to very nearly normal levels. Deletion of both copies of each of the two alpha-globin genes causes alpha(0)-thalassemia, also known as homozygous alpha thalassemia. Due to the complete absence of alpha chains, the predominant fetal hemoglobin is a tetramer of gamma-chains (Bart hemoglobin) that has essentially no oxygen carrying capacity.
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| | == Relevance == | | == Relevance == |
| - | Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs. If a hemoglobin test reveals that your hemoglobin level is lower than normal, it means you have a low red blood cell count (anemia).
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| | == Structural highlights == | | == Structural highlights == |
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| - | This view is created with SAT to <scene name="/12/3456/Sample/1">color</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.<scene name='75/752264/Derivatives/1'>Text To Be Displayed</scene>
| + | <scene name='75/752264/Residues/1'>The structure of Human Pepsin is similar to a serine Endoproteinase with molecular weight of 35 kd. the structure is divided into 3 domains. The main domain includes 6 stranded antiparallel beta sheet that helps as a backbone to the active site region. It is comprised of residues Val 1- Leu 6, Asp 149- Val 184, and Gln 308-Ala 326. The N-terminal is also composed of residues</scene><scene name='75/752264/Derivatives/1'>Text To Be Displayed</scene><scene name='75/752264/Derivatives/1'>Text To Be Displayed</scene>Hemoglobin |
| - | <scene name='75/752264/All_active_sites/1'>This new scene allows to see all active sites on the molecule</scene> | + | |
| | </StructureSection> | | </StructureSection> |
| | == References == | | == References == |
Revision as of 21:43, 26 April 2018
Hemoglobin
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Function
Disease
Relevance
Structural highlights
Hemoglobin
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References
https://www.ncbi.nlm.nih.gov/books/NBK11727/
https://www.tandfonline.com/doi/abs/10.3109/10409239509085142
http://pediaa.com/what-is-the-function-of-hemoglobin-in-the-human-body/
https://www.ebi.ac.uk/pdbe/entry/pdb/1gzx/index
https://www.rcsb.org/structure/1gzx
