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DMT1

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The predicted DMT1 structure contains twelve hydrophobic transmembrane proteins. Both amino and carboxy termini of the protein are intracellular. The polypeptide loop between transmembrane proteins 7 and 8 is predicted to have asparagine-linked glycosylation sites, is extracellular and longer than others.[1]

Iron-Responsive Element and Transport Regulation

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There are two known isoforms of DMT1 mRNA, one containing an Iron response element (IRE) while the other does not possess this IRE (non-IRE). The IRE is contained in the Three prime untranslated region in the mRNA, and is thought to be the reason for regulatory iron uptake properties in the Duodenum. Therefore, it would be expected that the concentration of dietary iron is inversely proportional to the mRNA expression. That is, when dietary iron is in low concentration then mRNA expression would increase to maximize iron uptake in the duodenum. Alternatively, when dietary iron is in high concentration mRNA expression would decrease to lower the iron absorption.[2]

Diagram of dietary iron absorption from the duodenum into enterocytes. Any ferric (Fe3+) iron present must be reduced to ferrous (Fe2+) by duodenal cytochrome b (Dcytb). Ferrous iron then undergoes transportation into enterocytes by DMT1.[3]

In a study performed by Gunshin et al., 2001, rats were fed an iron-deficient diet. After 3 weeks, the rats showed a substantial increase of 50-100 fold of the intestinal DMT1 mRNA levels, which indicates that intestinal DMT1 mRNA responds to cellular iron concentrations or dietary factors to attempt to regulate the absorption of iron. Although a substantial increase in intestinal DMT1 mRNA was documented, only minor increases (~1.5-3-fold) in kidney, liver, brain, heart and lung DMT1 mRNA was observed, indicating that duodenum DMT mRNA is much more responsive in terms of regulating iron absorption. [4]

Mutations Affecting Iron Transport

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Mutations occurring in trans-membrane domain 4 in microcytic anemia mice and Belgrade rats showed decreased transport of iron by DMT1. The transport of iron across membranes was hindered from:

  • the duodenum into enterocytes, and
  • plasma transferrin into erythroid precursor cells

Defects in DMT1 can lead due to reduced uptake of dietary iron, resulting in Iron-deficiency anemia[1]

Future Medication Applications

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IRE stem-loop structure of the 3’-untranslated region in a mouse, rat, rabbit, and human. The stem-loop structure remains unchanged (CAGUG) across the species studied. There is a single unpaired C as indicated with a box, and an unpaired U as indicated by a circle. It is possible that the unpaired U in the stem-loop structure can affect the structure of the IRE and interfere with iron regulatory protein binding, causing inhibition of feedback of cellular iron concentration.[5]

Some individuals have issues with an abnormally high concentration of iron in the body. A quite common disease known as Hemochromatosis can lead to toxic iron concentrations in the body, affecting the performance of the liver, causing joint pain and many other symptoms. These individuals may benefit from medications that inhibit the intestinal DMT1 transporter. [1]

Small Edits
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DMT1 also transports cobalt (Co2+) and lead (Pb2+).[4]

DMT1 functions best at lower pH's, at approximately pH=6. [6]

DMT1 has a molecular mass of 70-75kD.[7]

DMT1 was first identified in 1994 by Gruenheid et al. (1994).

Bacongirl78/sandbox
Chemical Structure
Names
IUPAC name
4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)
Identifiers
Properties
C36H24N6
Molar mass 540.62 g/mol
Appearance White powder
Melting point 340°C
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Toxic

Harmful if inhaled Causes skin irritation Causes serious eye irritation May cause respiratory irritation

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Week 3 Tasks - Info for 4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)

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Properties of 4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)

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  • Molecular formula: C36H24N6
  • Molar mass: 540.62 g mol-1
  • Melting point: 340 °C
  • Boiling point: N/A
  • Solubility in water: N/A

4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)

4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)

Chemical bond

4′,4′′′′-(1,4-Phenylene)bis(2,2′:6′,2′′-terpyridine)

Photoreduction of 2,6-Dichlorophenolindophenol by Diphenylcarbazide: A Photosystem 2 Reaction Catalyzed by Tris-Washed Chloroplasts and Subchloroplast Fragments[8]

Structural models for the metal centers in the nitrogenase molybdenum-iron protein[9]

Nitrogenase MoFe-Protein at 1.16 Å Resolution: A Central Ligand in the FeMo-Cofactor[10]

Chemical Properties of Reagent Ethanol and Isopropanol

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Chemical Chemical Formula Molar Mass / g mol-1 Melting Point / °C Boiling Point / °C
Ethanol C2H6O 46.07 -144 78.37
Isopropanol C3H8O 60.10 -89 82.6

References

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  1. ^ a b c Andrews, Nancy C (1999-10-01). "The iron transporter DMT1". The International Journal of Biochemistry & Cell Biology. 31 (10): 991–994. doi:10.1016/S1357-2725(99)00065-5.
  2. ^ Lee, Pauline L.; Gelbart, Terri; West, Carol; Halloran, Carol; Beutler, Ernest (1998-06-01). "The Human Nramp2 Gene: Characterization of the Gene Structure, Alternative Splicing, Promoter Region and Polymorphisms". Blood Cells, Molecules, and Diseases. 24 (2): 199–215. doi:10.1006/bcmd.1998.0186.
  3. ^ Belaidi, Abdel A.; Bush, Ashley I. (2016-10-01). "Iron neurochemistry in Alzheimer's disease and Parkinson's disease: targets for therapeutics". Journal of Neurochemistry. 139: 179–197. doi:10.1111/jnc.13425. ISSN 1471-4159.
  4. ^ a b Gunshin, Hiromi; Mackenzie, Bryan; Berger, Urs V.; Gunshin, Yoshimi; Romero, Michael F.; Boron, Walter F.; Nussberger, Stephan; Gollan, John L.; Hediger, Matthias A. "http://www.nature.com/doifinder/10.1038/41343". Nature. 388 (6641): 482–488. doi:10.1038/41343. {{cite journal}}: External link in |title= (help)
  5. ^ Gunshin, Hiromi; Allerson, Charles R.; Polycarpou-Schwarz, Maria; Rofts, Andreas; Rogers, Jack T.; Kishi, Fumio; Hentze, Matthias W.; Rouault, Tracey A.; Andrews, Nancy C. (2001-12-07). "Iron-dependent regulation of the divalent metal ion transporter". FEBS Letters. 509 (2): 309–316. doi:10.1016/S0014-5793(01)03189-1. ISSN 1873-3468.
  6. ^ Su, Maureen A.; Trenor, Cameron C.; Fleming, Judith C.; Fleming, Mark D.; Andrews, Nancy C. (1998-09-15). "The G185R Mutation Disrupts Function of the Iron Transporter Nramp2". Blood. 92 (6): 2157–2163. ISSN 0006-4971. PMID 9731075.
  7. ^ Canonne-Hergaux, François; Zhang, An-Sheng; Ponka, Prem; Gros, Philippe (2001-12-15). "Characterization of the iron transporter DMT1 (NRAMP2/DCT1) in red blood cells of normal and anemic mk/mkmice". Blood. 98 (13): 3823–3830. doi:10.1182/blood.V98.13.3823. ISSN 0006-4971. PMID 11739192.
  8. ^ Vernon, Leo P.; Shaw, Elwood R. (1969-11-01). "Photoreduction of 2,6-Dichlorophenolindophenol by Diphenylcarbazide: A Photosystem 2 Reaction Catalyzed by Tris-Washed Chloroplasts and Subchloroplast Fragments". Plant Physiology. 44 (11): 1645–1649. doi:10.1104/pp.44.11.1645. ISSN 1532-2548.
  9. ^ Kim, J.; Rees, D. C. (1992-09-18). "Structural models for the metal centers in the nitrogenase molybdenum-iron protein". Science. 257 (5077): 1677–1682. doi:10.1126/science.1529354. ISSN 0036-8075.
  10. ^ Einsle, Oliver; Tezcan, F. Akif; Andrade, Susana L. A.; Schmid, Benedikt; Yoshida, Mika; Howard, James B.; Rees, Douglas C. (2002-09-06). "Nitrogenase MoFe-Protein at 1.16 Å Resolution: A Central Ligand in the FeMo-Cofactor". Science. 297 (5587): 1696–1700. doi:10.1126/science.1073877. ISSN 0036-8075.