Glut3: Difference between revisions

GLUT3(<scene name='71/716527/5c65/1'>5c65</scene>) is a transport protein consisting of 481 amino acids and weighing 52,520 Daltons in its asymmetrical unit<ref name="nineteen">http://www.ebi.ac.uk/pdbe/entry/pdb/5c65/</ref>. This protein is an alpha-helical protein consisting of two chains, two different ligands and water<ref name="nineteen"/>. The structure was determined by X-Ray diffraction and was measured at a resolution of 2.65 Angstroms<ref name="twentytwo">http://oca.weizmann.ac.il/oca-bin/ocaids?id=5c65</ref>. GLUT3 consists of 12 transmembrane segments (TMs) folded “into the N-terminal and C-terminal domains, each comprising ‘3+3’ inverted repeats”<ref name="nine"/> These TMs consist of four 3 repeated sections. [http://www.nature.com/nature/journal/v526/n7573/fig_tab/nature14655_F1.html Here] is a figure by Deng, D., et al. showing these repeated transmembrane segments<ref name="nine">Deng, D., Sun, P., Yan, C., Ke, M., Jiang, X., Xiong, L., . . . Yan, N. (2015). Molecular basis of ligand recognition and transport by glucose transporters. Nature, 526(7573), 391-396. doi:10.1038/nature14655</ref>. The protein consists of two different ligands, Y01 and 37X<ref name="eighteen">http://www.rcsb.org/pdb/explore.do?structureId=5C65</ref>. Octyl Glucose Neopentyl Glycol (<scene name='71/716528/37x/2'>37X</scene>) has a chemical formula of C₂₇H₅₂O₁₂ and a molecular weight of 569 Da. There are six 37X (501-506a) bound to chain A of 5c65. These ligands are kept in place by hydrogen bonds to arginine, proline, and serine and by van der Waals forces. Chain B has three 37X ligands attached to it (501-503b). These are attached through hydrogen bonds by arginine, proline, and serine as well as by van der Waals forces<ref name="twenty">http://www.ebi.ac.uk/pdbe/entry/pdb/5c65/bound/37X</ref>. To view 37X in 3D use [http://www.rcsb.org/pdb/explore/jmol.do?structureId=5C65&residueNr=37X JSmol]. Cholesterol hemisuccinate (<scene name='71/716528/Y01/1'>Y01</scene>) has a chemical formula of  C₃₁H₅₀O₄ and has a molecular weight of 487 Da. One Y01 is attached to chain a and another Y01 is attached to chain b<ref name="twentyone">http://www.ebi.ac.uk/pdbe/entry/pdb/5c65/bound/Y01</ref>. To view Y01 in 3D use [http://www.rcsb.org/pdb/explore/jmol.do?structureId=5C65&residueNr=Y01 JSmol]. GLUT3 was also identified and analyzed in a complex with alpha & beta d-glucose. This model was reported with a resolution of 1.5 Å and was in an open-occluded state<ref name="nine"/>. The alpha and beta d glucose were coordinated in a <scene name='71/716528/Binding_pocket/8'>binding pocket</scene> by amino acids N315, E378, Q159, W368, Q280, Q281, N286. These are located on TM8 and TM10a and TM10b<ref name="nine"/>. A figure of this glucose coordination by Deng, D., et al. is available [http://www.nature.com/nature/journal/v526/n7573/fig_tab/nature14655_F2.html here]. GLUT3 structure was also determined when bound to maltose in an outward-open and an outward-occluded conformation. This was measure to a resolution of 2.6 Å and 2.4 Å respectively. A figure of this maltose coordination by Deng, D., et al. is available [http://www.nature.com/nature/journal/v526/n7573/fig_tab/nature14655_F2.html here]. To get a better view of the structure of the protein use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5C65 FirstGlance].