1iw9
From Proteopedia
(New page: 200px<br /><applet load="1iw9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1iw9, resolution 2.5Å" /> '''Crystal Structure of ...) |
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| - | [[Image:1iw9.jpg|left|200px]]<br /><applet load="1iw9" size=" | + | [[Image:1iw9.jpg|left|200px]]<br /><applet load="1iw9" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1iw9, resolution 2.5Å" /> | caption="1iw9, resolution 2.5Å" /> | ||
'''Crystal Structure of the M Intermediate of Bacteriorhodopsin'''<br /> | '''Crystal Structure of the M Intermediate of Bacteriorhodopsin'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Structural changes in the proton pumping cycle of wild-type | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1IW9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum] with RET, L3P and L2P as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1IW9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Halobacterium_salinarum Halobacterium salinarum] with <scene name='pdbligand=RET:'>RET</scene>, <scene name='pdbligand=L3P:'>L3P</scene> and <scene name='pdbligand=L2P:'>L2P</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IW9 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Matsui, Y.]] | [[Category: Matsui, Y.]] | ||
[[Category: Okumura, H.]] | [[Category: Okumura, H.]] | ||
| - | [[Category: RSGI, RIKEN | + | [[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]] |
[[Category: Takeda, K.]] | [[Category: Takeda, K.]] | ||
[[Category: L2P]] | [[Category: L2P]] | ||
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[[Category: structural genomics]] | [[Category: structural genomics]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:16:23 2008'' |
Revision as of 11:16, 21 February 2008
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Crystal Structure of the M Intermediate of Bacteriorhodopsin
Overview
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.
About this Structure
1IW9 is a Single protein structure of sequence from Halobacterium salinarum with , and as ligands. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Thu Feb 21 13:16:23 2008
Categories: Halobacterium salinarum | Single protein | Adachi, S. | Kamiya, N. | Kouyama, T. | Matsui, Y. | Okumura, H. | RSGI, RIKEN Structural Genomics/Proteomics Initiative. | Takeda, K. | L2P | L3P | RET | 7 transmembrane helices | Riken structural genomics/proteomics initiative | Rsgi | Structural genomics
