View source for 1iw9


==Crystal Structure of the M Intermediate of Bacteriorhodopsin==
<StructureSection load='1iw9' size='340' side='right'caption='[[1iw9]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1iw9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IW9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1IW9 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GAL:BETA-D-GALACTOSE'>GAL</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=L2P:2,3-DI-PHYTANYL-GLYCEROL'>L2P</scene>, <scene name='pdbligand=L3P:2,3-DI-O-PHYTANLY-3-SN-GLYCERO-1-PHOSPHORYL-3-SN-GLYCEROL-1-PHOSPHATE'>L3P</scene>, <scene name='pdbligand=MAN:ALPHA-D-MANNOSE'>MAN</scene>, <scene name='pdbligand=RET:RETINAL'>RET</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1iw9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iw9 OCA], [https://pdbe.org/1iw9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1iw9 RCSB], [https://www.ebi.ac.uk/pdbsum/1iw9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1iw9 ProSAT], [https://www.topsan.org/Proteins/RSGI/1iw9 TOPSAN]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BACR_HALSA BACR_HALSA] Light-driven proton pump.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/iw/1iw9_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1iw9 ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Structural changes in the proton pumping cycle of wild-type bacteriorhodopsin were investigated by using a 3D crystal (space group P622)prepared by the membrane fusion method. Protein-protein contacts in the crystal elongate the lifetime of the M intermediate by a factor of approximately 100,allowing high levels of the M intermediate to accumulate under continuous illumination. When the M intermediate generated at room temperature was exposed to a low flux of X-rays (approximately 10(14) photons/mm2), this yellow intermediate was converted into a blue species having an absorption maximum at 650 nm. This color change is suggested to accompany a configuration change in the retinal-Lys216 chain. The true conformational change associated with formation of the M intermediate was analyzed by taking the X-radiation-induced structural change into account. Our result indicates that, upon formation of the M intermediate, helix G move stowards the extra-cellular side by, on average, 0.5 angstroms. This movement is coupled with several reactions occurring at distal sites in the protein: (1) reorientation of the side-chain of Leu93 contacting the C13 methyl group of retinal, which is accompanied by detachment of a water molecule from the Schiff base; (2) a significant distortion in the F-G loop, triggering destruction of a hydrogen bonding interaction between a pair of glutamate groups (Glu194 and Glu204); (3) formation of a salt bridge between the carboxylate group of Glu204 and the guanidinium ion of Arg82, which is accompanied by a large distortion in the extra-cellular half of helix C; (4)noticeable movements of the AB loop and the cytoplasmic end of helix B. But, no appreciable change is induced in the peptide backbone of helices A,D, E and F. These structural changes are discussed from the viewpoint of translocation of water molecules.

Crystal structure of the M intermediate of bacteriorhodopsin: allosteric structural changes mediated by sliding movement of a transmembrane helix.,Takeda K, Matsui Y, Kamiya N, Adachi S, Okumura H, Kouyama T J Mol Biol. 2004 Aug 20;341(4):1023-37. PMID:15328615<ref>PMID:15328615</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1iw9" style="background-color:#fffaf0;"></div>

==See Also==
*[[Bacteriorhodopsin 3D structures|Bacteriorhodopsin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Halobacterium salinarum]]
[[Category: Large Structures]]
[[Category: Adachi S]]
[[Category: Kamiya N]]
[[Category: Kouyama T]]
[[Category: Matsui Y]]
[[Category: Okumura H]]
[[Category: Takeda K]]