1x0i
From Proteopedia
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|PDB= 1x0i |SIZE=350|CAPTION= <scene name='initialview01'>1x0i</scene>, resolution 2.30Å | |PDB= 1x0i |SIZE=350|CAPTION= <scene name='initialview01'>1x0i</scene>, resolution 2.30Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <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=RET:RETINAL'>RET</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1x0i FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1x0i OCA], [http://www.ebi.ac.uk/pdbsum/1x0i PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1x0i RCSB]</span> | ||
}} | }} | ||
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[[Category: Murakami, M.]] | [[Category: Murakami, M.]] | ||
[[Category: Okumura, H.]] | [[Category: Okumura, H.]] | ||
| - | [[Category: L2P]] | ||
| - | [[Category: L3P]] | ||
| - | [[Category: RET]] | ||
| - | [[Category: SO4]] | ||
[[Category: 7 transmembrane helice]] | [[Category: 7 transmembrane helice]] | ||
[[Category: membrane protein]] | [[Category: membrane protein]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 00:43:19 2008'' |
Revision as of 21:43, 30 March 2008
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| , resolution 2.30Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , , | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal Structure of the Acid Blue Form of Bacteriorhodopsin
Overview
Bacteriorhodopsin, a light-driven proton pump found in the purple membrane of Halobacterium salinarum, exhibits purple at neutral pH but its color is sensitive to pH. Here, structures are reported for an acid blue form and an alkaline purple form of wild-type bacteriorhodopsin. When the P622 crystal prepared at pH 5.2 was acidified with sulfuric acid, its color turned to blue with a pKa of 3.5 and a Hill coefficient of 2. Diffraction data at pH 2-5 indicated that the purple-to-blue transition accompanies a large structural change in the proton release channel; i.e. the extracellular half of helix C moves towards helix G, narrowing the proton release channel and expelling a water molecule from a micro-cavity in the vicinity of the retinal Schiff base. In this respect, the acid-induced structural change resembles the structural change observed upon formation of the M intermediate. But, the acid blue form contains a sulfate ion in a site(s) near Arg82 that is created by re-orientations of the carboxyl groups of Glu194 and Glu204, residues comprising the proton release complex. This result suggests that proton uptake by the proton release complex evokes the anion binding, which in turn induces protonation of Asp85, a key residue regulating the absorption spectrum of the chromophore. Interestingly, a pronounced structural change in the proton release complex was also observed at high pH; i.e. re-orientation of Glu194 towards Tyr83 was found to take place at around pH 10. This alkaline transition is suggested to be accompanied by proton release from the proton release complex and responsible for rapid formation of the M intermediate at high pH.
About this Structure
1X0I is a Single protein structure of sequence from Halobacterium salinarum. Full crystallographic information is available from OCA.
Reference
Crystal structures of acid blue and alkaline purple forms of bacteriorhodopsin., Okumura H, Murakami M, Kouyama T, J Mol Biol. 2005 Aug 19;351(3):481-95. PMID:16023672
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