Lactose Permease: Difference between revisions

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Savannah Anderson, Ralf Stephan, Eran Hodis, David Canner, Michal Harel, Alexander Berchansky

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 ===Structure of Lactose Permease===
 <applet load="1PV7" size="300" color="white" frame="true" align="right" caption="Lactose Permease" />
-<scene name='Lactose_Permease/Beginning/1'>Lactose permease</scene> is a transmembrane protein consisting of N- and C- terminal domains (depicted in this model by the blue and red hemispheres), each with six <scene name='Lactose_Permease/Backbone/3'>transmembrane helices</scene> symmetrically positioned within the permease.  There are six sidechains that play an irreplaceable role in the active transport of lactose through the protein.  Three of these sidechains, <scene name='Lactose_Permease/Glu126/3'>Glutamic Acid 126</scene>, <scene name='Lactose_Permease/Arg144/3'>Arginine 144</scene>, and <scene name='Lactose_Permease/Glu269/3'>Glutamic Acid 269</scene> have been shown to be crucial in substrate binding activities.  <scene name='Lactose_Permease/Arg302/2'>Arginine 302</scene>, <scene name='Lactose_Permease/His322/2'>Histidine 322</scene>, and <scene name='Lactose_Permease/Glu325/2'>Glutamic Acid 325</scene> are known to play a significant role in proton translocation(moving the H+ proton) throughout the transport process.  Additionally, there are two residues that are suspected to play an important role in the alignment of the galactopyranosyl end of the substrate.  These are <scene name='Lactose_Permease/Cys148/2'>Cystein 148</scene> and <scene name='Lactose_Permease/Trp151/2'>Tryptophan 151</scene>.
+<scene name='Lactose_Permease/Beginning/1'>Lactose permease</scene> is a transmembrane protein consisting of N- and C- terminal domains (depicted in this model by the blue and red hemispheres), each with six <scene name='Lactose_Permease/Backbone/3'>transmembrane helices</scene> symmetrically positioned within the permease.  There are six sidechains that play an irreplaceable role in the active transport of lactose through the protein.  Three of these sidechains, <scene name='Lactose_Permease/Glu126/3'>Glutamic Acid 126</scene>, <scene name='Lactose_Permease/Arg144/3'>Arginine 144</scene>, and <scene name='Lactose_Permease/Glu269/3'>Glutamic Acid 269</scene> have been shown to be crucial in substrate binding activities.  <scene name='Lactose_Permease/Arg302/2'>Arginine 302</scene>, <scene name='Lactose_Permease/His322/2'>Histidine 322</scene>, and <scene name='Lactose_Permease/Glu325/2'>Glutamic Acid 325</scene> are known to play a significant role in proton translocation(moving the H+ proton) throughout the transport process.  Additionally, there are two residues that are suspected to play an important role in the alignment of the galactopyranosyl end of the substrate.  These are <scene name='Lactose_Permease/Cys148/2'>Cysteine 148</scene> and <scene name='Lactose_Permease/Trp151/2'>Tryptophan 151</scene>.
 These sidechains, which make up the active site of the protein, can be found within the large internal <scene name='Lactose_Permease/Cavity/2'>hydrophilic cavity</scene> of the lactose permease.  It is here where the <scene name='Lactose_Permease/Sugar/2'>substrate</scene> is recieved for transport and it is the location from which it is deposited into the cell.  The currently crystalized form of the permease is considered an 'inward-facing' conformation.  This implies that the hydrophilic cavity mentioned previously is positioned with the opening towards the cytoplasm of the cell.  Conversely, and outward-facing conformation would have the cavity facing the periplasm.